I'd not go for the Honwave as the launching wheels are I think painful / expensive due to the built in hull extensions in the air floor ?
I had a 2.6 Excel SD airfloor, so so much cheaper than the honwave and I was impressed . Oh and the air floors are flat , with a keel underneath so not like the internal V of the Honwave.
I think they may do a 2.9 which would give some more room for kids & stuff. Slow speed I think you would get away with a 2.7 just not have much comfort which would be painful/ annoying after a while .
unless you stick 15 hp on it, then you'ld only get 6-7 knts out of it loaded up, 2 up and 6 or 8 hp I think would get you planing. And a 15hp start to weigh in for a 4stroke ..
Just my 2p worth ...
Edit - yes they do a 2.9m ;
http://www.excel-inflatables.co.uk/b...able-sd290.htm