I'm on a project at the moment which is also involving a complete (scuttle plus window apertures) roof panel.
The workshop manual suggests using oxy along the gutter tops to soften the metal. I have to confess that I only read that after I'd unpicked them (doh

), but once you get them started, they come away O.K.
As will be revealed sometime soon, the problem we've got is there is not actually very much to attach the new roof to. It's more or less a case of hanging the roof from the workshop ceiling, and building a new car underneath it.
Anyway, we're well underway, and as I get further I'll post up any tips that come to light.
Overall though, from what I've done / seen so far, I'd suggest that the 'proper' way is likely to be the only way, especially if you've already mastered doing the rear wing seam. Be a different story if it was a factory sunroof that was being filled, in which case Tea Boy's method (which was also what I did on my Gulf Blue car) would be my choice by far (lovely job, BTW: not easy to get that smart

).
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