a guy in the UK bought all the templates for these roofs, and does all the installation work. He puts small adds regularly in Practical Classics.

The Coune cabs are heavy, with 3 U-shaped reinforcements: one on each side (front pillar to end-of-seating compartment, runs under the doors - visibly less height) and one in the upper trunk space, from left to right, quite elaborate framework, leaving little space for luggage.
But well, you wouldn't use it for carrying stuff around, anyway ..
rgds,
john