Adding weight to SLS work...?

Quick back ground: I was a high school athlete: played soccer and track and field. I was always one of the guys in the best shape due to my love for fitness. I ran a lot. I built up to a 12.02 100m (not super impressive, but got me into States), a 55.95 400m a 11:09 2 mile. I only could probably only run a 12.25ish 100, a 57-58 400, and a 12-14 2 mile now, due to not practicing much lately. Right now I can squat 270lb for 5, while keeping a few reps in the tank. I can also dead lift 340lb for 3-5 reps. So I have decent leg strength for someone weighing 168 pounds,

I was considering adding weight to the SLS progressions, that way, when I arrive at the single leg squat, I could already do it with some weight. Also, the leg workouts are not very challegjing to me,

I'm on PE2 for the SLS, right now. Twisting squats are a challege, but I used to (and sometime still) do 10-15 Cossack squats as part of my leg warm up for my lower body lifting. I think twisting sqauts are hard just because it a totally new movement pattern for me. I did 2 sets of 10 and a set of 7 last time I did twisting squats (day 2 of week 1). So I'm confident they will become easier soon enough.

Back to my question: would is be fine to add weight to my PE2 squats? I would probably not add a lot of weight, like start out with 5-10 pounds and maybe build up to 20-40 or so. If I did so, I would drop or decrease the amount of heavy squatting I do currently.

(Sorry for any typos or grammar errors... It's been a tiring day, haha.)

I would say no until you can do mastery of SLS PE2/iM 2. 10-15 reps of Cossack Squats is nothing compared to 5 consecutive sets of 10 Cossack squats and 10 twisting squats with no rest in between.

Adding weight to the squats will just tire out your legs for the twisting squats.

If Cossacks really are extremely easy for you, then why not start on week 5 or 9 and work on bringing up the twisting squats? You should be able to complete mastery fairly quickly and then can move on.

Why would you add weight if you can't display mastery without weight first?

No it would not be fine. If you want more intensity, you need to fix your mobility deficit so you can progress further. 

If the twisting squats is only a movement pattern issue do some every day and you should have them mastered in 2 weeks. That way you can move on to the next level. There is some really challenging hamstring exercises in F2 that will test you

Thanks for the tips guys! I will not be adding weight, due to your feedback. I may try out starting at week 5, and practicing Twisting squats more often so the movemt feels more natural. I just assumed I shouldn't do week 5 because I could not do 3 sets of 10 twisting squats.

Mark, believe me, I'm really excited for F2... but I don't want to rush F1 too much. Patience is going to a challenge for me!

From RiQC on another thread:
 

 

If it is IM you struggle you can do later weeks in PE.

If you lack mobility in PE then you recycle the starting weeks.

 

Feel free to start at week 9 for any exercise where the iM is the limiting factor.

Alright. Cool. I think I'll stick with week 5. Week 9 would be quite the challege, and I think I'll take my time on this one.

Thank you guys, once again, for the help!