What comes to mind concerning the "glop"..........To me it looks like it is from a lot of excessive moisture, maybe from all the pickle juice/mustard slather? I don't know your set-up, was there a waterpan in there?
When I have done chuckies, or any other meats for that matter, I usually dry them real well with paper towels before putiing on my rubs and what not.
not sure where else to go with it.
Weber Performer with rotisserie ring, 22.5OTS, Maverick 732, Weber Smokey Joe,PBC Smokenator/Hoovergrill, variety of microbrews, Gin and tonic, variety of lighters.