Hi, I'm sorry to hear you've had a bad experience with Don, since I recall roughly a year ago you asked to hear from people with good experiences and I was one to respond. I can't relate to the problems you've had, as I've bought 2 of my 3 Western saddles from Don, 1 from another supplier and I've not experienced any problems, either in fit or comms. All I can say, though, is that I have 2 QHs which are quite different but fairly easy to fit, I haven't asked Don to fit a non-QH. Maybe you should seek out someone who regularly fits non-QHs, I suspect Maria Owen might, Sequoia Western do too but again you need to be careful who is actually doing the fitting itself - but in any case, if you've experienced problems with 2 saddles so far, may be worth really investigating where the problems lie. I like the sound of that impression pad, could be useful just anyway.
On an associated point - are you absolutely sure that rubs are being caused by saddle/blanket? Sorry if that sounds ridiculous, only last year my TB mare was getting (so I thought) a rub on one side from her Western saddle/blanket. Turns out - since I've been riding her mostly in an English saddle this winter - that it's actually caused by an under rug, nothing to do with the tack, and is now appearing on both sides of her loin where the rugs are twisting slightly.
Good luck in getting your saddle sorted though, there's nothing more worrying and frustrating.