I think I’m missing the logic of cutting down the spring.... if the bushing is wearing down, then it’s probably moving excessively, ie, something’s not tight. The 26” shocks that you’re currently using have been used for years on similar levels of rear lift with no known issues.
Additionally, no matter what spring you put in the rear, your suspension will still travel and move the same as it always has, thus moving your shock in the same manner as before. The problem is with the shock- it’s bushings, or how it’s been attached.
Just my $0.02