I use Gamma Supreme overgrips. If I'm playing frequently, I'll wear through the top layer and the fabric underneath will give me good traction for a while. If I play only now and then, the dirt from my hands will mix with the tacky surface and make it feel gummy. I have some Dunlop Viper overgrips on order. I wonder if I'll be able to adjust.
Dunlop MuscleWeave 200G 95, Cyberflash 1.25/Hexy Fiber 17 @47/51, Alpha Pioneer DC+ dropweight