Well the worlds most famous two-seater Spit still hasn't been done, unlike the more conventional Tr.9 model which has the rear as a raised canopy 407 has the Grace-inline-conversion which means both canopies are at the same height.
I'll be glad to help out with this project, but I've never seen a two-seater model Spit EVER for ANY version of FS
Come on designer chappies!!!

Ozzy