Hey Terri - I replied to this yesterday - no idea why it isn't here??? In any case.
First of all - unless you have a good airless sprayer - not a "buzz gun" (Wagner) - I would not spray. Any sprayer that requires you to thin the paint is not doing you any favors. Thinning paint can be very harmful to it - loss of sheen, washability, flexibility, change of drying times - the list goes on - all can result from thinning paint.
If you only have a few doors to do - remove them and paint them with a brush - it isn't too bad (did two myself this past fall!)
If you have a lot of doors - look into renting a professional airless sprayer - they will spray paint without thinning it. They cost anywhere from $50-$100/day - they need about a quart of paint just to get through the hose - so you are going to need gallons of whatever you are using.
Speaking of what to use. I always recommed Glidden...so...
Glidden Ultra-Hide Gripper (primer) sand after this dries (4-6 hours) - and then two coats of Glidden Ultra-Hide Eggshell or Semi-Gloss - Glidden Evermore Satin or Sem-Gloss - or - Ralph Lauren Semi-Gloss - your choice of color