hellowyo the Lyman 429421 is a cast bullet of about 250 grs. It's very accurate and does a fair job on game. At 1200 fps it's probably more gun than you're wanting. For this reason you most likely need something besides 296. Now it's good powder and works best for above standard weight bullets but is not to used for loading down. It's designed to work best and be stable at higher pressures
2400 has loaded down fine for me over the years but it is dirty when you start letting the pressures drop. Elmer used 22 grs. with the same bullet I use. The powder has changed somewhat over the years I guess but I've kept my load at 20 grs. because 1200 fps is plenty for me with a standard weight Keith or RNFP.
You need something like Unique, 231, or AA 5. These powders will let you shoot your little cannon below 1000 fps. If you get a 200 gr. bullet to 1000 fps the Redhawk will feel more like a 357.
S&W Junkie makes a very good point about noise. The larger bores are easier on the ears. I was reminded of this a while back when I came upon a copperhead just east of my house. I was walking up the hollow and drew my 4" M-19. The load was a mid-range 357-170-K load. One shot, dead snake, and several hours of ringing ears. A 44-250-K mid-range load wouldn't have been near as bad sound wise. It's a rare for me to fire a sixgun without something in my ears, but sometimes it happens and when it does I'd rather have a 44 or 45.
Even with all the pro's I have concerning the 44, I'm tempted to go with the others here who suggest the 357. After all Skeeter said if he could just have one it would be a 5" M-27 S&W. AND it will do the 99% of the chores I need done.