Is there something very unique about your measurements that precludes off-the-rack ordering? It’s kind of unusual anymore for a person not to fit well into some maker or other given how many calf and height options are available these days (and how many full elastic panels).
I think how often you plan to ride in these boots, how precious you’re willing to be with them, and how long you’d like them to last will (or should) make a huge difference in the recommendations you’ll get. If you’re looking for a tall boot for daily wear (and to pick a stall here and there, bring a horse in from turnout, etc.), I would personally steer away from the super fitted, “leather sock” Parlantis and others like them unless you’re willing to replace them quite regularly at considerable expense. IMO, their thin, ultra-soft leather, while lovely, just isn’t made for kind of use.
If if you’re looking for something that will wear like iron (as your GP’s probably did) with daily use and proper care, and if you really do need custom, I still don’t think you can go wrong with Dehner or Vogel.