Tube Suggestion....shooting w/Housing?

I have an Aqua Tech D2 water housing for my D300. It is currently set up to shoot with a Tokina 11-16 f/2.8 wide angle. Right now we will just be shooting from the housing...though I am working on a housed strobe system using RadioPopper PXs.

I don't think I want anything giant...as that will make it harder to get the tube from one side of the wake to the other...and position it where you want. We ride in the Delta...so you don't have a lot of room to use the boat to move the tube around...and that messes up the water anyway. I was thinking of something simple and flat like the LF 60"....or 72" Party Islands. Does anyone have much experience shooting from a tube. Any nuggets of wisdom are appreciated...especially regarding safety, etc.... With the 11-16...we will have to be very close to the rider. Should make for some cool shots.