I've found out the hard way it's best to go ahead and get what you REALLY want, instead of something "good enough". We all do that, and buy something that's pretty good, but then we buy the next best one, then the next, until we finally buy that one piece that we really wanted at the beginning. We wind up spending a lot more than if we'd just gotten The One right at the beginning. Problem is, what is "The One"?
GMTs are notorious for bad crown guards, bad hand stacks, cobbled together movements that really aren't supposed to have a 24h function, and on and on. That's the reason RWG is here... to share information about watches. So my advice is to read, read again and read some more. Look at posts by our inimitable @By-Tor ... the man has forgotten more about GMTs than the rest of us have ever learned. Over the last 10+ years he's gone into excruciating detail over what's good and what isn't on the GMT offerings. See what he has to say and learn what to look for.
Armed with that knowledge (no more guessing now) look at what the TDs offer and pick the best one you can find. Seriously, stretch yourself and go for the BEST. Don't wuss out.
Then when it arrives it will be more than you hoped for, not less. If it needs a service (likely) send it to MyManMatt or Misiekped and be gracious. They are artists and deserve our patience and respect. Then when you get it back wear it for a month, take lots of pictures, then start a pictorial topic and show us your pride and joy. Tell us the story and we'll celebrate with you.