I agree with you that the BB GMT is really big. It was one of my purchase shortlist watch but AD told me to put full deposit onto it and i will be placed on the 19th waiting slot. I did not proceed as I need to try on the watch before making a purchase decision.
End up, I bumped into a nice chap across a cafe wearing that watch. I went over to strike a conversation with him and tried on the watch. to my surprise, the watch look damn good on pics and the internet but not so well balanced on my wrist. Its too think in my opinion. I'm glad I didn't place the deposit.
That being said, it does look good on that chap's wrist and his wrist is noticeably smaller than my wrist. Might have something to do with the angle tho.. the front profile looks great !
If I were you, I will put it on a leather strap with contrast stitching [alot bespoke strapmakers out there] to carry the gmt. Make sure the strap is thick enough so it wont be top heavy.
In any way, the watch is a great watch and you should enjoy it to the fullest since you got it already ! Imaging 18 people placed full deposit to wait for the watch ! and that's just in ONE AD !
take care, regards,