Thanks for the suggestions but the glue phase is almost over. Jen polyester resin (Bog) is no good, it melts the foam, I tried that this arvo. Mark, the dome is reinforced to the ring using wood triangles, see inside the dome in the image, and it works too well. I used nomorenails to glue the dome down and a combo of pva and nomorenails to glue/screw the wood. It's not going anywhere and that has been proven this week with the wild storms that have swept the city. But honestly, it needs a glue with a gap filling ability comensurate with my abilty to build stuff
I have filled the gaps around the shutter with canned foam and will reattach my wooden triangles between the shutter and the dome internally for strenght. I have pulled the shutter into shape with hooks and string but fully expect to have to make a new door and window, when these storms stop of course.
I'm still tossing up if I will spring for fibreglass or just do render for the skin. It's $20 compared to about $400. Weight is the main difference I guess, 6 kilos compared to 40Kgs, and as it is, 2 of us can still lift it on and off.