First, good luck finding a Ruger Alaskan in 454 Casull. They are catalog items, but there are none in production. You will need to scour gunbroker.com and gunsamerica.com for one. Be prepared; they're going for around $1,000-$1,100.
I too would spend most of my shooting time shooting 45 Colt. 454 Casull is just too much. Regular 44 Magnum is too much for me out of my Ruger Alaskan, though I can generally get through 12 rounds with ammunition at 1,200-1,300 FPS.
Ruger does chamber the Super Redhawk with 7 1/2" barrel in 454 Casull. You may want to go this route and have the barrel cut to four to six inches. Hamilton Bowen can do it and offers several front sight options. It won't be cheap, but you'll have the gun setup exactly how you want.