rear disc conversion issues

Hey guys, I need either some advice as to what to tackle with my brakes or a recommendation as to which shop in the Riverside/San Bernardino, California area to take my Duster to.

I installed a rear disc conversion kit from Right Stuff Detailing (http://www.getdiscbrakes.com/) as well as new front calipers and rotors and a new master cylinder (but kept stock booster). Has anyone used their kit before? I have been having all sorts of issues and have been on the phone with Right Stuff at least once a week trying to sort this stuff out.

First issue I have is a soft pedal. The brakes work fine and grab well, but the pedal feel is virtually non-existant. Right Stuff said this was due to the emergency brake being out of adjustment, so I fixed that to their specs. They also said it could be air in the rear calipers trapped during bleeding, since the bleed screws have a bit of a downward angle. So I pulled those off and held the screw parallel to the ground and bled the brakes as normal. Still a soft pedal, though the brakes seem to be working fine.

Second issue is the big one that's upsetting me. After going forward and back in my driveway about 6 times (20-50 feet) then forward and back in my cul-de-sac (250-300 feet) I ventured to go to the end of my street (1/4 mile) and the brakes locked up and did not release. This same thing happened last weekend, and again today. Right Stuff suggested that the pushrod coming out of the booster and into the master cylinder piston was too long and not allowing the fluid to return to the master cylinder when the pedal was released. So I pulled the master cylinder and screwed down that push rod until it was at it's shortest point (1/8 inch shorter, which is about what Right Stuff said it should need). Still the same lock up problem, so I laid under the car and cracked each bleed screw enough to get it back in the driveway where I gave up for the day. I've read that a residual pressure valve for a drum brake system would cause this issue, but Right Stuff said this Master Cylinder would not have those installed, I will be checking that first thing in the morning by pulling out the tube seats and seeing if there's a pressure valve in there.

Does anyone have any suggestions as to what could be causing these issues? I've spent the last 3 weekends working on the brakes with nothing improoving and I just want to drive the car. Car was originally a power disc front and drum rear car, now power discs on all 4 corners. Any help or shop recommendations are greatly appreciated. If I can't get soemthing to change tomorrow I'm calling a shop and tow truck first thing monday morning.