There was a thread on this a while back, le mond wedges, ive done a search for that but cant find it, there was another more obscure name being used that I cant remember, if anyone can remind me maybe the thread is still active.
Anyhow the gist of it was that when the guy actually went to a cyclefit place the cure was actually the opposite of adding the wedge in the usual way, so reckon coatesy advice is right and you need to get some proper help rather than trial and error.
Was it you that posted the other thread coatesy?
chucky, be careful the BG shoes have a 1.5 degree of wedge built into them, at least they used to.
Edit.. I worked it out on CAD how much was needed uder 1 side of the cleat to match the 1.5 deg spesh build in and it was a lot lot less than the thickness of a washer, more like just a few 100ths of a mm..