I fyou are going to use light ply and screws, be sure and harden the holes with thin CA before you screw in. As a matter of fact, its a good idea to screw in the screws, take them back out and then re apply the CA so that the threads themselves are hard. Do not even bother trying to do this in any type of balsa. The vibration will very quickly cause the screws to wallow the holes.

A trick I read, but have not tried for the RC56 Canopy Glue is to put it in the freezer and let it gel. Then apply it. That way you can get it exactly where you want it and by the time it warms up it will already be in place. Otherwise its like trying to work with water.