The molded fuse could come in 2 halves. This way you could create a slot or groove in the front for a firewall to be placed. So when the 2 pieces are snapped together to be glued the firewall would be held in place by the mold of the fuse. It would work like a clamp around the wall, you could put a bead of glue in the groove before the wall is held in place by the 2 halves.

Also, it would be much easier to install pushrods, and wires with the plane wide open, I have big hands so working in tight spots is a real pain.

Again, I want to stay away from the spads and such because They look like crap. Besides, a realistic looking combat plane like this would be great for sport flying as well.

A much larger more expensive example of what I have in mind are produced by http://www.aerotechmodels.com/P51.htm

These are made from carbon fiber and look sweet, picture this in 1/12th scale and made from cheap/lightweight/tough plastic.