I've sprayed doors before and they turned out fine, I setup a drop cloth behind hung from the ceiling. Had two short 2x4's on the floor to set the door on. then one leaned against the wall in front of the drop clothe to only the top edge touched it, that way I could paint both sides and then leaned it against another wall at about a 30-45 degree angle with just the corner touching the wall to let them dry. It let me stack several of them in a short space that way about 3" apart. If you've got any varnish on the doors, scuff them up with some 100 grit sandpaper first to get a good bond before spraying primer. I'd use a gloss or semi-gloss latex for the finish.
To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault