We don't really do many repaints, we do a lot of new const. paint jobs. All the G.C.'s we work for want latex paint on all there trim and doors.
When spraying new doors, with or without a grain pattern,.when using latex, if you get a run, or sag, don't try to get out at that moment, let dry there first. this way you get a even finish.
Now the way to get rid of the run, or sag, is to take lacquer thinner on a rag, and rub that area and wipe it off..It's like washing your mistake away..
This works on dried latex, and oil...then before rehanging your doors, respray that area, to keep the same smooth finish...No sanding needed...
This is the fastest and easiest way to remove latex and oil runs ,and sags..And it really works.
The problem with using a small roller, at the time you get you run, or sag, is that now you have two different textures on your door. When dried ,that doesn't look very good...
Even the best spray people get runs or sags...I've been spraying for 27 years, and at times i still get runs, or sags... but with my little trick to fix them, i don't let it bother me anymore....s**t happens...