Watch the Funky Slide online guitar lesson by Vicki Genfan from 30 Strumming Patterns You MUST Know
I'm using a G7-C9. You can leave the 1st string open and let it give you the added 13 color tone. If you don't want to hear it you can mute it. Make sure when you slide you just play the first three strings. Play around with using more or less chicken scratch and see how you like it. Play around with accenting different (chicken scratch) beats to get more syncopation.