I hate to be the one to tell you, but you are never going to get a quality tire out of the Motor City unit. No dressing will deliver a decent tire from an inferior piece of equipment. As someone who has spent countless hours with this machine, I am telling you: You are engaging in an exercise in futility. It was put out on the market with virtually no field testing, and it shows in the results. Anyone who tells you they are getting a well-dressed tire from this machine is lying to you(or has sub-standard expectations).
To date, though not perfect, the Simoniz Tire Shiner is the best out there. I've heard good things about the Belanger Durashiner, but have no real hands-on experience with it. It's certainly worth a good look.
Consider it a very expensive lesson and pull that thing out of your tunnel. Don't ever buy any piece of equipment without seeing the results it can deliver first.