As for magnums in a J Frame, most people are NOT going to like it. Try before you buy a J Frame magnum, or if you can't, just find an old pickup and slam your hand in the door jam. If it doesn't hurt, you'll probably be fine with magnums .
My point remains-you don't have to shoot magnums in a .357 Magnum revolver; you can shoot mild .38 Special wadcutters for the rest of your life if you so choose. But, if you so choose, you can always shoot magnums. Which is why a .357 Magnum revolver is so much more versatile than an identical revolver chambered in .38 Special.