Alan your almost right, its 80mm on the rear and 215mm on the front or there abouts anyway.

50 flips is about right assuming we run on gas and dont start pulling liquid. 100 flips would be possible I guess if the temperature remained constant and there were no leaks but its hard to tell as we use the flippers randomly depending on which way were heading.

Also we can run with upto 4Kg on board if its a warm day but 3Kg is more the norm.