Cheers guys!.
I should point out that I had originally thought of doing the domes as a series of ribs & skinned in styrene with the old pizza wedge method, which works, but decided this would create a headache to get the various pits in situ, especially the big underside pits!. Having the domes as shells means the area underneath is mostly hollow, a part from a rib at the 12, 3, 6 & 9 positions which hold up the quarter domes. I'll decide at the time if further ribs are required, maybe an overkill, but only when the pits are positioned.
I should point out that I had originally thought of doing the domes as a series of ribs & skinned in styrene with the old pizza wedge method, which works, but decided this would create a headache to get the various pits in situ, especially the big underside pits!. Having the domes as shells means the area underneath is mostly hollow, a part from a rib at the 12, 3, 6 & 9 positions which hold up the quarter domes. I'll decide at the time if further ribs are required, maybe an overkill, but only when the pits are positioned.