Well I re-measured the fluted pvc pipe and it's actually 3" square not 3 1/2" like I posted earlier. The final size with the 4mill wrapped around it is pretty close to the 3 1/2 mentioned.
As it always seems I get a bit carried away with the poly glue when building the coro fuse with the pvc formers....but I haven't had any of the glue joints fail so I guess it's ok.
As promissed here's a couple pics of the new creation:
The tailfeathers:
The spads balsa brother:
Madd_Maxx