Best epoxy primer

the devilbiss would be a good primer gun.
the epoxy primer is a good idea if you keep it out side at all, just make sure you get a real epoxy primer like http://www.valsparrefinish.com/primers_other_VP50.jsp
the spi epoxy primer looks like it could take forever to apply and dry. it has a pot life of up to 5 days and requires a 30 min set time before spraying so it could be very slow drying. i have not used it though so my opinion is only based on the TDS.

if you dont have a primer picked already i recommend house of kolor kd3000. ive been spraying it with a pos husky hvlp from 2009 or so, and it self levels to no orange peel and is easy to sand.

if you want bc/cc you might want to invest in a better gun. i got a devilbiss plus form tcp global for like 450 with a bag style cup kit. so far ive shot single stage base and clear with it. the single stage and clear didnt need polishing.

for a solid color single stage the finishline should be fine. you might want to try the other guns though to see witch is least orange peely. please dont do a metalic single stage. i did and im taking it all off.

if your compressor can handle a extra slow leak and you dont mind having a tail you could go with a fresh air hood.