I have the Right stuff detailing front disc conversion I put on my '69 Roadrunner.... I do not have slop between the caliper and pad and the rotors are flat. Came with the necessary clips and banjo fitting type hoses. But, I had issues as well. One of my spindles was not machined to the right tolerance. For the life of me I couldn't get the the bearings over the spindles. Had to send it back, got a replacement and it worked fine.
On another note..and I would research PST's kit on this as well; My car was 4 power drums, just the same. Well the problem is that the Right Stuff booster kit is designed to work for converting manual drums to front power disc....not Power drum to front power disc. If you have a power drum car, the bracket off the back of the booster is completely wrong to match the setup under your dash. It can be made to fit.....With serious modification. I ended up researching a lot of the kits out there and a great majority of them are all the same...manual to power disc. So...beware. I ended up having to buy/find a Mopar Bendix power booster and sent the Right Stuff's booster back to them. When I ordered they specified it would fit right in, when I called and told them "this isn't going to work", I got a "ohhhh yeah...that won't work!"
I agree with Doug on the rears.......I have the 11" HD police/taxi rear drums on my bird, and that's more that adequate with the front disc. Like mentioned, unless you're going pro touring or something, why waste the extra money and headaches of trying to make rear disc work on your car? These cars are heavy, there is no "anti-lock" feature and the drum Brake hardware/parts are cheap and easy to find. Your car, your money..