I have a 24' Kayot pontoon with a 70 HP Johnson.Just out of Idle curiosity was wondering if a hydrofoil would have any positive effect on a pontoon whatsoever.
Probably not as much as a mono hull but it should help.
It is certainly worth a try and I really doubt it will hurt anyting or make it perform worse.
70 horse on a 24 is not exactly over powered so don't expect miracles but it should ge tthe back of the boat up alittle and you may even get a tiny bit more speed,like 1-2 MPH,speed on water is hard to come by.
toons are not planing hulls, the foil may add a little lift, but most likely will add more drag, than lift. i believe you will loose performance. propping the motor correctly will do more good than anything.