I can't say that firing pin movement bothers me at all - I have a TOZ-78 22lr rimfire rifle with the same thing and I've never developed a flinch. If you do have issues with flinching due to the firining pin moving, perhaps purchasing a TOZ-78 could solve this problem due to the fact that is has no recoil.
Anyways, the only time I developed a flinch was after shooting alot of slugs with my shottie.. when I went back to rimfire, I realized I had developed a NASTY flinch. The first step to eliminating the flinch is to understand the flinch.
Flinching is caused by your body anticipating the recoil, the sounds, the sights, all the fantastic magic that happens when you pull the trigger. I find the best way to eliminate a large portion of the flinch is to wear appropriate eye and ear protection. Good muffs will cut out all external noise and put you in that zone where nothing can bother you - save the recoil of the rifle. Good glasses will give you the confidence that no dirt/dust/smoke will get into your eyes. Good protection can convince your body that the 'danger' of shooting (to which it is reacting with a flinch) is not significant.
Now eliminating the flinch due to recoil is another story. The only way to really work this is to start small (ie rimfire) and work your way up. When I developed my slug flinch, I shot nothing but rimfire for an entire month. When I finally moved back up to an intermediate round, I made sure I wore my muffs and glasses, and ensured that I had a good grip on a gun that fit me well (in this case, my SKS-D). To make sure the flinch isn't creeping back, shoot a few rounds of rimfire after shooting your medium caliber weapon. After the medium caliber weapon has been re-mastered, you can move up to the bigger stuff, but once again, make sure you shoot some rimfire after each session to keep the flinch from creeping back.
You have to realize that the flinch is simply a subconscious reaction to a violent experience - your body predicts that there will be a big bang, some smoke and a kick, so it reacts. You have to TRAIN your body to not react this way, train your body such that when you pull that trigger, your body either doesn't expect a violent reaction, or doesn't care.