With regard to the front panel fitting, having done it twice now, you will need to tap the top of the inner front panel down slightly in the area of the "step" inboard of the headlights. Then make some reasonably generous holes for the bonnet mounting bolts and fit the bonnet, sandwiching the front panel in place. This will also allow you to get the bonnet/front panel gap right and consistent. Once you have that correct its just a matter of pulling the front panel down and screwing it in place, work from the top down. Dont worry if it has to come off more times than a tom's drawers, that's how it works! Don't forget to get the wings fitted simultaneously.
When you are completely happy with the fit, take it all off again, add a generous seam of Tigerseal to all the mating surfaces and refit with the screws then leave for the Tigerseal to set. Once its dry its there for good and you can, if you want, remove the screws and fill in the holes with more Tigerseal, however, being a belt and braces man, I left my screws in place except for a couple that fouled the grille fitting. The wings may need thinning a bit on the top face and just forward of the second bulkhead.
You weren't kidding with the front panel fitting!! after 6 months of looking at it I started to have a fettle last night, its certainly going to need some pulling down!
What did you do to mate the lower wing edges to the front panel? I'm thinking speed fasteners?