hey
probably a bit late, but:
I've been round the workshop a lot working on my Z and the prep work for the paint is taking ages, (i took it all the way back to bare metal and have built up from there). Now, I'm by no means an expert but the workshop has (arguably) the best Z panel and paint man around in it.
and one of his little gems of wisom, was that the more surfaces/layers there are, the more layers can fail. On their quick jobs they just sand it really thoroughly, but for a full car job, it's worth blasting and doing a bit more work, you'll end up with a better car.
just my opinion and observations........just wish i could finish painting my bloody one!!!
Huw