Vacuum Advance sticking?

The car came with a nice set of TRW forged pistons that were in great shape, so I just couldn`t see the point in replacing them.Now I`m thinking maybe I should have. I`ve read somewhere that you can remove one of the advance springs to get a faster initial advance. Is this true? This weekend I`ll get a chance to tweak the idle mixture. I thought maybe that was the case.Linkage and all is fine,(no clearance issues),that was one of the first things I checked. Do you know what is average idle mixture setting on these Holley carbs? I`m at 1.5 turns out? I`ve tried to set them with a vacuum gauge and tach but a good base point would be helpful. Breather= air cleaner, southern slang!I thought everyone used that term.Thanks again for your help.