I carry a G20 with a lone wolf barrel, stainless guide rod and *I think* a 24lb recoil spring (the heaviest one they sell). It's a bit over sprung as I get an occasional stove pipe with hot loads in 200gr, the 220gr BB ejects fine though. I need to get a slightly smaller recoil spring as I don't shoot 220gr any longer, I'm fine with 200gr.
Accuracy is very good with the LW barrel. Next project for the gun is swapping the sights out for trijicon night sights.
I also have the S&W .40 cal lone wolf barrel for the G20 and I use the stock recoil spring with that, its very sweet to shoot the .40 with the bigger gun than a typical .40 platform and the shooting is cheaper. Good practice ammo. Next I want to get the 9x20 dillion barrel for hunting thinner skinned game but I might long slide it for that.