Two-watch Dive Setup: GMT Master II left wrist, Daytona right wrist?

[$ In Da Banana Stand]

I was thinking of seeking out a Sub Date or an SD for diving expeditions, but I've learned, frustratingly, that neither will do everything I need.

If I am diving and I swim from one timezone to the next, a GMT II will surely be essential for keeping up with time in my new time zone and the time zone out of which I just swam. Additionally, I may need to gauge how fast I am swimming/diving, and the tachymeter on the Daytona will enable me to do that with ease.

Neither of those features are offered on Rolex's seafaring watches (which is a big disappointment, to say the least), so I'm thinking about pulling the trigger on the GMT II and the Daytona and wearing one on each wrist when I dive. Has anyone else done this before, and if so, how did it work out for you?