I am on TRT too and presently on-cycle (Primo and Test). I can make gains while just on TRT, although they are more modest of course. Actually I trained for almost two years on just my TRT dose and did just fine.
your going to more less hold nto your gains form cycle better..if you make gains they will be minimal and it will be after your body has adjust from the higher doses
You can make gains naturally so there is no reason you shouldn't be able to make gains on roughly 3x your natural test levels. If you half-ass your training and diet because you tell yourself you're off progress will be minimal.
Man I blow up on 350 mg test. 200 is still a lot of extra test. I think you could make great gains on it if your diet and training are cool. Not full cycle results of course but still great gains.
I am. Have not done a cycle yet but my wife and friends are noticing a big diff in the way I look just from the TRT,diet and of course working out. Will be doing my first cycle as soon as I get my fat level down to around 12%.