First off, this is my first post, so hello to everyone, and thanks to Coach Sommer to making this resource available and to everyone on the forum for being so great with answering people's questions. This seems like an awesome community and I've learned so much already. I hope I can get comfortable enough with the GB program to help answer others's questions and give back. I have some questions sprinkled in with my plan, and then some at the end that didn't really fit in.
I'm currently 27, 6'0, 200 lbs. Not sure about body fat, but I can pinch 1-2" on my stomach with my fingers. In the right (dim) light, I can see some abs 
I used to lift weights, but haven't in over 3 years.
Nutrition: Back when I was still lifting, I didn't have a 6-pack, but wasn't as soft as I am now. I'd like to at least get back to where I was before, but that's secondary to strength and developing the FSPs. I realize that I need to work on my nutrition, and plan on adding tons of veggies into my diet, getting more meat, completely cutting out soda, and limiting caffeine intake. I've read slizzardman's thread on pre/peri/post WO nutrition and plan on implementing that as well, but with fewer carbs until my work capacity is up and I can have a "real" workout. I'll still be taking in more carbs than I would really think I need otherwise.
Equipment: I have a pullup bar in a doorway with multiple grips, with straight handles (like 5" PVC with foam around it) suspended from it. There's room to do pullups, supports, levers, dips, rows, pushups, but can only do dead hangs with bent legs, and could probably also do inverted hangs with bent legs, haven't tried yet. Are rings significantly different from just using handles like these? I'd also like to make a mushroom for circles, but I probably have a long way to go before I'm ready for that.
Current plan: I've read BTGB at least once straight through, and reread several parts a few times, plus I've been lurking on the forum for months reading whatever I could. A few months ago I tried doing a workout where I would do the wrist series to warm up, then go straight to working tuck PL and tuck FL, figuring that the prereqs were only for people who were too weak to do the actual FSPs. Only kept with it for a few weeks. Tuck PL always made my left forearm ache. Since then I've read a lot more and have realized that the prereqs are here to stay. I can do 60s once and 30s x 3 on the 6 basics that are in my plan, but I didn't see if I could do 60s x 3. Honestly 60s once was rough and I didn't feel like trying to do it twice more. It's been a few years now since I've had a serious exercise plan, so my work capacity is way down from what it was before I stopped lifting. Going to do 3 days per week for now. Law school takes up a good amount of time and frequently cuts into sleep, so I probably couldn't handle 4 days unless I really get my act together.
Warmup:
1-arm kettlebell swings/low pulls/high pulls with 35 or 50 lb kettlebell for 15 or 20 reps to get the blood flowing
Ido's scap mobilization routine
Wrists: pushups where I go up onto my finger pads at the top, and the ones on the back of my hands
I haven't tried dorsal pushups, but I'll give them a shot in my next workout and see how they feel
Prereqs:
PB support, hollow, reverse plank, dead hang, plank, arch.
Holding each for 30s, cycling them all w/ no/minimal rest, for 3 rounds. So 90s total for each.
This is part of what I'm confused about. I've read that they're good for training as an SSC (which seems like total should only be 60s), but I can already do at least 60s. I've read elsewhere that it would be good to just do each to technical failure. For now I plan on sticking with 30s x 3 to help build my work capacity up for at least 4 weeks, unless 90s each seems like too much. Or would it be ok to, say, add 5-10s total per prereq per workout?
HS work: 10min
Currently everything is against the wall, don't yet have the balance for freestanding. I'll just hold for 10s, then get off the wall a bit and try to freebalance, keep falling back to the wall and repeating until I go to far and have to come down. Rest for a bit, then go back to it. Last time I really shrugged higher and my traps felt great because of it. Going to really make shrugging high a priority.
L-sit PB: 20s x 3
Should I be trying to turn my elbows out like on PB support? When I do that, my triceps seem to contract way harder. It feels nice so I'm happy doing it that way, but I'm not sure which form I should be reinforcing.
Also, once I can hold my legs high enough to work it on floor, does it matter which way I point my fingers?
FBEs:
Day 1: Pushups/rows on the suspended handles 8 reps x 3 sets
I know I should be doing lower reps, like 3 or 5, but I'm not sure how I can make the rows much harder without adding resistance. Would it be fine to do tuck FL rows before I actually start working the tuck FL? Or should I just do something like 1-arm rows?
Would it be more beneficial to progress the pushups by using a resistance band or just shifting to more of a PPPU?
Day 2: HeSPU/chinups
In my last workout I only went down on the HeSPU to a 5" block for 3 reps, but it seemed pretty easy, so I'll either go for 5 reps next time or go down to 4" or 3"
Day 3: Dips/body curls
I can do several (haven't tested my max) dips on the suspended handles, but not sure my elbows are really ready. I don't get sharp pains, but it sounds like tendonitis isn't something that just happens one day.
Even with a significant lean, I have almost no ROM on the body curls. I think my body is 30-45 degrees. Is there a previous progression I should be doing instead?
I'll do core and legs every day.
Core: Pike compressions and straddle circles
On pike compressions, is it better to move my hands farther out and get my feet just barely off the floor?
I'll add straddle compressions in once my hips open up some more.
I also do bridges randomly, but they're not really programmed in anywhere. Usually just regular floor bridges, but sometimes wall rotations into bridge.
Legs: Jump squats for now. I have the strength and stability to handle SLS, but it's been a while since I've done strength work for my legs, so they may be too much for my knees currently.
For prereqs, I've seen 30s x 3 in some places and 60s x 3 for times I should have before I start PL/FL/BL work. I'm not going to add any in for at least 4 weeks so I can see how my elbows feel and I know if I'm doing too much too fast, but when I think I'm ready, should I go ahead and add in those progressions or keep waiting until I get 60s x 3 on the prereqs they need?
There's probably tons of holes in my plan, and I still have tons of reading to do, but are there any major ones? Like "If you don't do X then your elbow will literally explode."
Do I really need to work RTO supports before I start GH, or is that only if my elbows have issues with the GH? If I need RTO supports, do I need 30s x 3 or 60s x 3?
Once I'm much more proficient at a position that effectively incorporates a prereq (L-sit PB incorporates PB support, I think?), do I still need to do the basic prereq? Right now I only have pushup handles, and plan on making parallettes soon, but either way I won't be able to do a PB support with straight body and legs.
Thanks for taking the time to look at this 