It is always tricky to get a good fit when your feet are a bit different. When boots are tight in their width, there are only a couple of options.
You could try sizing up. This may not be the best option as the wider foot is shorter, but some different lacing techniques can help compensate for that.
You could try stretching the boot with a shoe stretcher. This one is also tricky because the GORE-TEX membrane could be compromised if you try this. You may want to call your local REI, as some shoe departments have tools to selectively stretch different areas on boots. Wearing them for a longer period to break them in may help as well.
Finally, and I know you don't particularly like this option, you could try a different boot. Something like the Salomon X Ultra or the Oboz Bridger may work, and both are available in wide sizes. I hope this helps!