Most go with a coarser sand due to the big fish kicking it up and constantly giving you a cloudy tank. as for the deepness. i would say atleast 3 inches. More sand, more filtration. and filtration is a beautiful thing.
i have 2 puffers in my tank 9" golden and 6" porcy, never had a problem with them clouding the tank, i have the fine sand and seeded the sand with ~80lbs of LS, so far no issues, been setup for ~7-8 months now.
