trying to fut my mirrors...ARRRRGH! help please.

[Uber Affe]

I should have had the holes filled when I had the chance before the pint when on and now there'll be fifty bajillion holes in the side.
Bottom line: I'm trying to fit my Talbot replicas to the side and finding that the metal is rather thin around those areas and the bolts are rather long.
I'm guessing spacers, but considered chopping the bolts down.
Ant who...It's just a huge pain because the spot they're going is seemingly impossible to reach from the interior side of the door and it is turning into a real bitch to get the screws to stay 'til they are in the holes...if and when they ever reach the thread holes!
Any of you run into a sinilar proble here? Did you just cut out a big hole for your tools to fit or figure something else out?

If this is too erratic to follow..let me know and I'll explain better.
Damn it! so close to completion!!!!!!