Ring support holds to supplement my F1+H1 workout?

I'd like to incorporate ring support holds into my workout routine, my question is  is it safe to do 3-5 short holds after each workout ( I workout 5 days a week). I know that ring training could lead to injuries if done prior to building a solid foundation of basic strength but at the same time I know that ring support is a very basic hold so I hope it could compliment my main workout. 

Thank you for any advice in advance

all depends on your strength/mobility and we all know what coach's answer on that one is going to be "First things, first." support holds on the rings are a sequel to PB support, so if you absolutely -must- workout support holds, PB would be your first go-to, to avoid getting too far ahead of oneself until all the basics are taken care of. 

i've noticed that as mobility and strength has gotten better, the humerus sits differently in my shoulder socket while in a support on the rings and can change where it sits by either holding the rings with my palms towards me, RTO or the aforementioned with a bit more clearance between the body and the rings. so, having a surplus of basic strength affects where the more advanced movements create strength without creating dysfunction from that anecdote. wanted to share that as a tangible reason to exercise common sense and not that it's all about forcibly staying behind just cause Coach says so. 

If you want to do more, I suggest doing more of the stuff at or just above your current level in terms of your Foundation progressions.  For example, if you're anywhere near where I am it's likely that an extra Jefferson Curl or a few form-refining dislocates would serve you better at this stage of the journey.  The sooner you master this stuff the sooner you'll be able to safely and effectively take up ring work full-time.  

One of the thumbnail images on the cover of R1 is of rings support. I have yet to purchase the product so I cannot be certain, but it seems that if R follows the pattern of F in that the cover shows images of the movement patterns contained within, then rings support may be one of the basic moves worked in that course. If it is, then the indication would be that even a basic rings support is beyond what most pracioners' bodies can safely handle. However, if starting with the recommended strength gained from F4, it doesn't seem to make sense that achieving basic support on rings would still take a number of cycles anywhere near what it takes to complete from start to finish the moves in F.

I used to train ring support before Foundation came out. It gave me some kind of over-use injury. My shoulders would ache through the day, so I gave it a bit of rest, and after a week or so, I felt good to train again. And the pain came back, and I rested again, and being stubborn, persisted going back on them. Repeat this over and over again. The thing was though that each time I had to rest to heal, the rest required was longer. Eventually, I did no training for like a month before the pain went away.

Training on and off like this was not productive and I did not make much if any progress in the end.

Then Foundation came out and I started training that instead. The pain went away and now I am making progress on the F1 materials. So, my personal advice would be to just take things in the order coach recommends. That has worked much better for me at least. The support holds will be there eventually, when you are ready for them according to coach's plan.

If you just want to toss in some ring support for fun and variety, then by all means give it a shot.

If you're planning on adding work sets of ring support to your routine, that's a bad idea. At this point in your training you have little to gain and much to lose from such work. Rings support doesn't work any muscles that you're not already working in Foundation, and it carries a much higher chance of irritating your elbows.

Joshua Slocum said:

If you just want to toss in some ring support for fun and variety, then by all means give it a shot.

If you're planning on adding work sets of ring support to your routine, that's a bad idea. At this point in your training you have little to gain and much to lose from such work. Rings support doesn't work any muscles that you're not already working in Foundation, and it carries a much higher chance of irritating your elbows.

So if I want to do it for fun and variety how often and how much can I do if I want to play it safe? 3 sets of 10 seconds once or twice a week? 

Bit of a subjective question really, something you'll have to judge yourself through a bit of trial and error. Err on the side of caution your progress will suffer more from an injury than it will through working below your perceived training level for a bit. Then once you've tested the water a bit you can make your own more informed decision. 

Keep the hold time to something that feels easy for you. A few sets a week should be fine.