You will find the fuse details of the flatback models in the #27 Aero Detail book. It has many three-views and photos of the Mk V1 to Mk XV1 The Soviet site below has three views with the fuse sections shown. I am building the 83" BT Spitfire with the flat back and bubble canopy.....Its not difficult to modify the plans.
See mine at:
www.members.shaw.ca/mcdougall.imports/www/ [projects page]
http://www.aviacherteg.narod.ru/avia...e/Spi_ML-3.htm