Back in my early pattern days when I used to paint fiberglass fuse's I too would have bleed under the tapes.
The only sure way I found to prevent this was to first lightly spray, like with an airbrush, a couple passes of clear followed immediately by the color.
This way if there was any bleed under it would be the clear and no harm.
Pinholes...
Are you spraying any kind of primer as part of your surface prep?
Can all be sanded off before the color but will show any imperfections like the pinholes.
I was spraying on the Gulf Coast of Texas.
VERY high humidity.
I had trouble with "fish eye", which can look like pinholes, caused by small amounts of water getting into the airlines.
Even with a water trap put between the compressor and the hoses I was having trouble.
At the time I was using K&B paint.
I talked to the guy there who told me I needed "fish eye preventer".
I thought "yeah right".
But there is such a thing.
Go to an auto paint supply place.
They have it in little bottles with an eye dropper to put just a couple drops in the paint.
It completely eliminated the fisheyeing.
I'd do some experimenting first though.
Hope this helps!
JLK