Get the 454, and just load it to 45 levels! My buddy had a 454 SRH, and loaded at ruger only 45 colt levels, ie 320 gr @ 1300 fps, it was suprisingly mild to shoot, and accurate.
I haven't shot enough of the SRH 454's to comment on accuracy, but my 480 SRH is scary accurate. It has shot so many different cast bullets into 1" 5 shot 50 yd groups, that I consider 2-3" 50 yd groups as so/so accuracy.
I've fired a buddies 44 mag Redhawk, and I greatly prefer the Super Redhawk. Despite the snipes that say the Super Redhawk is bulky, it is actually lighter then the Redhawk.
The 454 doesn't have to be a beast to shoot if you load it down. With my 480, my most used load is a 310 gr cast over 9.7 gr unique for 950 fps. It is not a recoil less load, but is mild enough to shoot all day long. Milder yet are 400 gr cast over 7 gr unique for 700 fps.
The best thing about big guns is they can always be loaded down to be smaller guns, but small guns are always smaller guns.