These are my 2 white dialed Rolex, and love them a lot.
As for a White GMT... Hmmm, not sure. I see very well what you're referring about, I'm nt a expert, but I would stay away from these White 6542s.
A very controversial watch, to say the least.
Now, IF rolex decided to release a pair of 6542s, one white, the other blzck, in a decent size, I would certainly be in.
Best,
Nicolas.