Was in Dick's getting some Shaky Heads and Zoom Shaky Head Worms in Watermelon w/red flake and the guy working the department told me that he fishes shakys year round and him and the guys he fishes with dips the tails of every worm in chartreuse garlic dip and that they have seen their level of bites increase dramatically. Has anyone else tried this on soft plastics?  

Yes

I use zoom trick worms and JJ's Magic. Yes it has increased my catch rate. 

Interesting. Reckon this would be effective on Spinnerbait and Chatterbait trailers? 

Yes

I use JJ's on watermelon and GP colored baits a lot, especially for smallmouth or when they're eating bluegills.