@John McDonough , thanks for that. I don't have trx but do have rings, hung from my conservatory rafter. To the original question: using trx with kbs and s&s. When I started s&s, I asked the forum about mixing it with muscle up ring training. Pavel suggested that it would be a lot of grief for the shoulder. So I ditched the muscle ups and focused on s&s. So the question is what is it you intend to do with trx? Strength, mobility, skill and volume of? And will there be conflict with s&s, or indeed be of assistance to it? A hybrid session of kb and trx? If done for mobility, probably would be OK, wouldn't it? Done for strength? Then maybe scale back s&s. Or, as is quite often stated, get to simple first, then see where you are at, what you need/want to do.
My rings are hung ready for use on a daily basis now for pull ups and rop. For a while they were down - with sighs of relief from my wife - and now they are back up I pop up for some hanging, a couple of skin the cats and the odd inverted hang. So, yeah, I literally hang out with them on most days. Wonderful.
During s&s, where I reluctantly had to take them down for large chunks of time and after a stupid incident with my old knee, I dropped the get ups for a bit and did hanging leg raises on rings, some presses and onto windmills before getting back into the get ups again when ready. Hanging leg raises and heavy get ups as s&s? No way. Too much, for me anyway. As a temporary strength component minus get ups, great. So back to the question, why mix trx? Mobility, probably fine, strength, be careful and aware of what your goals are. And in the context of s&s, the simple goal is the goal.