Good work Nick,
Q, Is the roof trimmed back as far as its going to go? or does the new roof panel fit up to where the spot welds are, ie are you just waiting until you new roof panel to turn up, before you trim back further?
I would also strongly recommend that you don't use Tigerseal to bond the panel in place, its not structurally ridged enough, its simply the wrong product for the job! Instead, use windscreen bonding adhesive, with the correct primer that it'll come with, you'll need 2 tubes, and about £15ish off ebay
Thom