How well are they equipped to handle large size man ?

I'm 6'8" and had no issues getting down to the platform. Had to duck down a bit on the stairs. I brought my own snorkeling gear so you may want to call ahead about sizing.

Honestly, not knowing how large exactly, i can tell you, it would be difficult getting down the stairs to the platform, it's a tight passage and by this point you should be all gear up. It may be worth recon prior to commit

The snorkel gear is not affected by this but i am unsure about the scuba diving.