i'm going to start manufacturing of bodyshell, but slabside or fia ?

[Buzz]

It's a good look, Oz! Be careful - you may start getting requests to put it into production.
Looking at the profile shot, it remindes me a bit of the hardtop assembly that the British replica manufacturer Gardner Douglass (sp?) used to offer. The gullwing doors were incorporated into the top assembly and the whole thing could be installed or removed relatively easily. It didn't incorporate the windshield and frame like yours does though.
My wife Pauline will be passing through your neck of the woods in july/august as part of a trip and Greek Isles cruise with her family - I should get her to stop by and take some pictures of your project!