Hi Dan.
I am 6'2" at 90kg. But, I will have 118kg worth of outboard hanging off the back, as well as a 30kg crank battery and around 15kg of fuel...at rear end..
Sharky - the 4.1m is rated at 50HP form factory, except I just had it re-rated for 60HP by a Marine Surveyor.
I do understand what you are saying about calm waters and going WOT - I will only be using this rig in the long river runs here in NT - so always calm.
I will be doing runs of 80km one way, so hence max HP desired...should be fun!!
Splash