I shot .44 Specials and Russians in my Ahrends wood-stocked 629MG for years before 'trying' those new Hogue .500 Magnum grips made for S&W. They really helped with the recoil of the UMC 180gr SJHP .44 Magnums I tried, some really hot rounds easily found for comparison. I bought a new 6" 629, SKU 163606, several months later just to use those grips (8/05). I replaced my MG with a new standard 4" - again, another one of those .500 Magnum grips - the best $35 you can spend on a hard hitting recoil - and they fit K/L, N, and X-frames... but they are only available from S&W Accessories. I did measure my trigger finger extension beyond the trigger guard when laid out alongside, in an attempt to determine the additional 'reach' required by the new Hogue's covered backstrap. My Ahrends square conversion f-g cocobolo stocks gave me nearly 3/16 inch more 'extension' than the Hogues. The wider smooth trigger of the 6" 629 (and 4" 629) make them feel comfortable with those new Hogues, as sad as that is to say for a wood stock person (Everything else I have has wood stocks!). My hands are medium in size, and those grips take the sting out, although, as you'd expect, the muzzle rise is still there.
Shooting milder loads may help, but shooting with your normal loads - and a few empties - in DA only - will give you more feedback. Have someone watch you, too... with good ear protection. You should 'know' when your DA hammer will drop... not so you can flinch, but so you will know what you are shooting. Practice this with your revolver unloaded, to determine the 'break'. Then, practice with real ammo. My personal 629 shooting included enough real Magnums to tell me I didn't 'need' them, having had my fill of launching high KE rounds with the .454 SRH I had for years. I now stick with 300gr LSWC's at 900 fps and 240's @ <1,000 fps for my high-end 'fun'... but I did buy the 6" 629 to replace a 6.5" 24 in .44 Special, anyway. The main goal here is to determine YOUR need - and work towards it.
Stainz