If you are interested in a good recoil spring setup for shooting 45 Super, the one I bought for shooting 460 Rowland would probably fit the bill nicely. It comes with two external recoil springs of different strength and it has two internal recoil springs also. It seems to do a good job buffering the recoil of the Rowland, which is significant even with the compensator the kit comes with.
http://www.dpmsystemsusa.com/Springfield_c_16.html