RE: Hangar 9 Tribute 36 + YS63 FZS ??
If you have that much pressure in your fuel tank, then something's wrong. Pressure in the fuel tank should only be slightly more than the atmospheric pressure outside the tank. This goes for any glow engine setup except for pumped engines. As far as the YS .63, well, I have a .46 AX on mine and it runs ok. I had to do some modifications to the fuse (cut out the engine mount, epoxy the wing in place, reinforce the tail wheel and add about an ounce of weight to the bottom of the rudder). Other than that, you might have to modify the main landing gear, I just barely had room for a 12" prop.