I've owned, reloaded for and hunted with both the 4" Model 29 and the 5 1/2" Redhawk. They were about equally accurate. I beat the poor old S&W silly with heavy loads, to the point that it had to be rebuilt once and was getting loose again when I traded it.
The 45 Colt is my bigbore cartridge these days but if I wanted a 4" heavy D/A sixgun, I would definitely buy a Redhawk. The 4" barrel is no handicap at all.
“Nine-tenths of tactics are certain, and taught in books: but the irrational tenth is like the kingfisher flashing across the pool, and that is the test of generals. It can only be ensured by instinct, sharpened by thought practicing the stroke so often that at the crisis it is as natural as a reflex.” ~ T. E. Lawrence