IMHO the Survivor stock is the most versatile stock available for a Handi.
The thing I like about the Survivor is that you can easily add or remove weight. When bench shooting my 30-06 or 270, I add about 6 pounds of BBs to the butt stock. I imagine a 12 pound 45-70 would feel pretty nice compared to a 7 pound one. When hunting, I remove the weight and then have a nice light carry gun. I never feel the recoil when shooting at game anyway.
I also agree with quick about the Limbsaver. I use one and love it.
I just recently made a BB bag out of old denim. The bag weighs 4.5 lbs and slides in to the storage area easily. This makes adding and removing the weight super simple and fast.
As for the recoil comparison, here is what I found at chuckhawks.com
Cartridge (Wb@MV) Rifle Weight Recoil energy Recoil velocity
.30-30 Win. (150 at 2400) 7.5 10.6 9.5
.45-70 (300 at 1800) 7 23.9 14.8
As you would imagine, it looks like the 45-70 kicks more than twice as hard as the 30-30. Not only 2x harder, but also with a 50% more snap.
Hope this helps,
RW