I will still use zesty Italian dressing as a binder at times. Most of the time I just apply moderate amount of rub directly on the meat lately. I always seem to get great smoke rings, even when using the Italian dressing. Getting flavor into the meat has never been an issue for me. I want the meat to taste like meat.
The only thing I use mustard for is sauce, mainly Shack Attack. I actually don't care for mustard, but it works in the Shack sauce.
Modded Brinkmann Gourmet. Basic UDS. Rescued 22.5" OTS. SJS Mini-WSM. Stubbs. B&B Oak Lump.
Cannondale 2009 F8 (for burning off all the great BBQ)