RE: U-Can-Do 3d 46?
Glassing the firewall is a great idea if you have access to it.
No plane needs more weight, but with the rearward CG of the UCD 46 front end weight is not a penalty.
I still can't believe that with a Saito 0.91 in front and a sub-C cell battery pack right behind the tank I am still 3/4" behind their most rearward recommended CG.