good luck finding powder right now. I found the best powder to be #7 but use what you can find. you are still under max on your loads and can get more if you really want to, i am getting 2000 fps with mine, the recoil was stout as you described until I put a brake on it and now it is a pussycat. with that said it will kill anything you shoot with it at reasonable ranges. good luck with your 375 and post pics when you kill.
still Dave Thomas, just an alias so the gov't dont find me