Slowing down the engine a bit is one thing I do to deal with wet grass. I go slow, watch the discharge and move at a pace that allows even discharge and no or minimal "spitting.". Single cut only and then just hit any clumps and windrows with the big backpack blower.
What mower do you have? I have a Bob-Cat with the Dura-Deck. It's ok. I like my Exmarks better but they're pretty heavily baffled too and no better cutting wet.