Dave Patrick's Edge is almost made to order for a 50 -and is very strongly built.
I did one a couple of months ago - and it was truly a rocket -
frankly I simply didn't care for the model so I sold it -same day - less engine .
The funny part was it is NOT designed for gas - yet--built bone stock -it was tail heavy with the 50 and an in cowl header and large can muffler I made.
I had to move the batts way forward to get a decent snap recovery .
It could be good 3 D model - with some time spent setting up throws .etc.
This one was exactly 15.25 lbs and no add ons whatsoever.
The ne owner just bolted in a 40 and Pitts muffler -and it still goes very well.
As for the horrible pipe setups - yes -they can be a pain but a decent setup can be done with a short can , which fits partway into and along the cowl bottom and over the gear plate.
Better than blowing a bunch for another engine
We have to hold in air noise down here - so the short muffler (not a tuned setup) works pretty good . Also you really can't see it on the ground and is not noticable in the air.
Another trick is do some prop experimenting with shorter blades -and different pitches .
Your 80 should work well on say a 26x12 Menz's clipped and thinned a bit .
I have tried that combo and was very pleased with the results.
Mike McConville- who did the H9 stuff -told me about the various combos they run .
His , has an 80 single with in cowl stuff and works very well - but the one with the GT 80 - which they sell also does a good job once they redo props and mufflers to spin it up over the 7000 mark a fair bit .
The Zenoah's have to really rev to work well.
I have a stack of props I play with which sometimes produces a prop once thought of as a ho hum -which becomes a winner - on the right model /emgine combo
It' fer sher all the chatter about a "best prop"- is just that -
you have to match the setup .
On 3D-- too many times - the flier goes to a large prop - the engine is really not running up in its best power band on hover/ high alpha stuf etc., -so some prop re think can can change things .