I'm also new to FT & was doing some range finding & wheel marking/clicking today. What I noticed was that there is definitely a position you are most comfortable & stable in, if you stray from this in any way, like turning your torso to the target rather than getting into the correct position, it will really show as your muscles are more strained. I can see that stock fit also plays a large part in this, mine needs a little more depth in the forestock ideally to get the best from it.
Obviously if you drop from 50 or 40 mag to 30 or lower it will help alot as it shows less wobble, but you probably already knew that
Breathing definitely is a large factor also, I never really noticed how poor my technique was when shooting HFT, I hold my breath far to long before releasing the shot & being a lefty my heartbeat really shows up through the rig !
I'm looking forward to shooting my 1st comp with the complete set up to see how I get on, I managed 30ex50 with my HFT set up at the Essex 50, but I think I will set my goals alot lower than that, as I think I will be lucky to hit 10 now, haha !