Wet Sanding...

Yikes! Seems like a long way to go to get a nice finish. If your
problem is brushstokes from the paint, there might be a few simple
factors, nothing too technical or complicated. One being that the paint
is supposed to flow, keep the temps at around 70°F which will let the
paint settle and flow. Do not keep brushing over an area that has just
been painted, this only thins the already drying paint (it starts drying
once applied) and raises ridges. Leave it alone and let it smooth
itself out. The next coat will catch what the first coat missed.
Another is do the work in a dust free environment, not in a room that
has carpetting. After sanding, clean with a tack cloth. Use a good
brush, the better the brush, the smoother the application. This is a
door and not a car so 10 coats might be considered a wee bit excessive.
Depending on how much and how close the scruteny your project receives,
you might consider using a semi-gloss as the slight defects do not stand
out as much as with a high gloss paint. Lastly, some defects add
character and charm so if all else fails, just say, "I meant to do
that."

~Kroozr