I have a suggestion for you:
Drop the idea of a glow engine on planes this size. Do you have any idea where to even get a glow engine for a 95" plane?
A 77" or 80" plane just lends itself to gas--way more than glow.

I waited 4 or 5 yrs before I got my first gas engine. Then spent the next 2yrs kicking myself for not doing it sooner. Gas is so great. Glow engines on bigger aerobats is NOT the best way to do it. The fact is that they are NOT lighter than a gas counterpart. For a 50cc glow engine--you'll need a 32oz tank for about 10 minutes worth of flight time. For a 50cc gas engine, you'll need a 10 or 12 oz tank for 10 minutes of flight time. That extra 20oz of glow fuel weighs a lot. Fill a 20oz tank sometime and weigh it.

With a glow engine--your forced to put your fuel tank behind the firewall. The plane is nose-heavy when you take off, and the elevator trims change as you fly the fuel out of the tank. You want the tank on the CG with a big aerobatic plane like this. It will fly smoother. It will fly the same at the beginning of the flight as the end of the flight. Trying to put the fuel tank on the CG with a glow engine is an exercise in beating your head against a brick wall. Only way to avoid it is to buy an $800 YS engine with a pump--or use a Cline regulator on your OS, or Saito engine.

With a gas engine--you get to use a smaller fuel tank. Thats a big weight savings. (20oz of extra fuel with the glow engine is 1.25 POUNDS!!! ) [X(] And, you get to put it on the CG. The gasser carb will pull fuel from the tail if you want to put the tank back there. Doesn't matter. The engine won't lean out. You can put the tank on the CG and just plumb it up to the carb. Adjust the needles once for break in and once again after 5 or 8 gallons. Then your done screwing with the needles--unless the altitude or temp changes significantly. Just fuel it and go fly.

If you want to 3D with a 77--85" plane--then you'd be a fool to put an unreliable glow engine on it and hover it down low. Glow engines die. Glow engines need the needles tweaked before every flight. Glow engines use very expensive fuel when compared to the price of gas/oil mix. They just aren't as reliable as a gasser.

Gas engines start easier. Gas engines are more fuel effiecient. Gas engines are more reliable in a hover--down low-- when a flameout would cost you $1500. Gas engines have more torque. Big prop--low pitch--for hovering. Lots of grunt.

Just bite the bullet and get a 40--50cc gas engine for your plane. You'll be so much happier in the end.