Robbie - I'm just a dopey old wireman and not a contractor, but I'm also involved with project management, contacts and estimating. From my perspective I can answer all your questions with one single answer, and that is I just wouldn't do the inspections at all.
Look at it this way, you have a resi customer or (worse) an insurance company who are trying to find someone who will make a determination that the alu wiring is safe. You really don't need to see it - it's not. What I mean is, even if it's OK today, it will deteriorate tomorrow, and unless it's regularly maintained (which you cannot control), it won't stay OK.
The insurance company really worries me - they're likely looking for more than mere assurances, you might be bitting off more legal liability than you know.
'fraid I'd run,
Radar
