I have just put a Limb Saver on a 458 Lott Ruger #1 and it has made a huge difference. My MarlinG will punish however with full bore (Garret like) rounds but I intende to put one on that as well.
I live in the country and pushed up a small burm at the end of my drive way which allows me to shoot a couple or four rounds every day. It doesn't matter what I shoot, I just shoot something. A squeeze of a couple of 375 HH, or a couple or .22, 44 mag., the 458, 45-70 or what ever. It doesn' matter. I shoot; that is the main thing. Over a couple of months, I have found that recoil out of just about anything doesn't bother me nearly as much as before and I a MUCH better shooter.
Shoot your rifle as much as you can and focus on the sight picture and the recoil will not bother you. And NO you will not learn to flinch. The only time I flinch now is at the range when some one is shooting a heavy caliber Browning with a Boss next to me.