Glock 17 lightened slide issues

[Bill9212002]

So I am running a Glock 17 gen4 with a Loki tactical uncle gespacho slide, rmr with amerigo sights and a alpha wolf threaded barrel.  I have run the factory RSA and I have noticed some severe marring on the inside of the slide where the barrel makes contact with the top of the slide.  I've run about 3-4 thousand rounds through this firearm.  Since I have ordered a higher quality threaded barrel but I believe I have to change the RSA spring weight.  I'm still at a loss if I need to put lighter spring because I have a lighter slide or a heavier spring to slow the slide.  Can anyone directly answer how this correlates?  Also, I run all kinds of ammo through this gun.  How will this affect my reliability?