The model I feel will need a tailplane, also known as horizontal stabilizer.
Also I would put a fin, with rudder, in line with the prop wash. Change the two fins to fit at the end of the tailplane, and non moving. I know you will need all 3.
Hang angle could be the same as the PT25 not sure what that is, but if too much it will still fly, not enough and it won't.
I would agree to make the nose higher and get more air under the blades for takeoff.
Make a wire frame like the Profile Kellet perhaps.
These are only my ideas, hope you don't mind.
Nice to see another idea, well done
. I think there are lots of old helis that could be converted.