Let me explain how I make a manoeuvre:
1 - Engage and hold down trimmer
2 - Fly the manoeuvre with the trimmer held down (You will get used to this, make sure it is the easiest to hold button on your stick)
3 - Stabilize her after the manoeuvre
4 - Release the trimmer while you center the stick. Timing and experience is crucial here to avoid bouncing. You can imagine that if you release the trimmer, there is a new 'center' position of the stick. If you hold your non-ffb stick in the same position it will be instantly in an off-center position, causing a bounce if you do not center your non-ffb stick.