I had a buddy back in VA who got pretty into it. You can make yourself some jigs with some threaded dows and wood blocks that screw outward to put pressure on the inside of the boot while you heat gun the outside. I think he used two nuts and got a wrench to crank the wood outward. Defintely takes a few hours to build a dialed jig like that though.
Also you can look into heat molding your liners in the oven.
I also remeber he used to mess around with forward lean shims, buckle placement on the boot & ramp angle on the board board - so lots of stuff to play around with.
Also, check out the adheasive foam that places like tognar sell. You can cut youself out some custom shapes, put them on the outside of your liner, and you can get your heel nice and locked in.