The Ruger Super Redhawk uses grips with the same internal attachment system, so they are interchangeable with GP-100 grips. The Super Redhawk, being available in much more powerful calibers, has larger/cushioned grips available for it, such as these Hogue Tamer Monogrips, available from MidwayUSA:
Hogue Tamer Monogrip Grips Ruger Super Redhawk, GP100 Rubber Black - MidwayUSA
The wrap around the rear of the grip frame, and add a cushion to the area of the palm that gets hammered the hardest in recoil. You can look around your local area, and if any shops have a Ruger Super Redhawk on the shelf, ask to handle the weapon and "try it on for size" to see how the grips feel. The weight and balance won't be the same, but you should at least be able to get an idea of how well the grips fit your hand. The Super Redhawk Alaskan (3" barreled "snubbie" in big magnum calibers!) also has the same mounting system.
"Placement is power" -- seen in an article by Stephen A. Camp
(RIP, Mr. Camp; you will be remembered, and missed)