Magnum outfitters in Edorado has some places to hunt in West Texas or can advise you who does. The Fantails as we cal them here have an extremely limited range, mostly the Oak and Pinon canyons over 4,000 feet elevation. In some areas they interbreed with the Texanis white tails which would some what diminish the experience for me. He doesn't list Carmen Mt. deer but probably can help you out if not provide a hunt. https://www.magnumguide.com/?aspxerrorpath=/magnumguideservice/default.aspx

Numbers are much higher in Mexico and I had a great hunt a year ago and will do it again post pandemic. With a good outfitter there are few problems.

There is also a guy who posts on here as Muley Mike and he has places on both sides of the border and maybe some Carmen possibilities too.