POR15 has a tech support section. Give them a call, they can tell you more than I can.
Top coating POR15 is easy. use one of their top coats, primers, or per their instructions, prime with your favorite primer when the paint is still a little tacky, then spray with your favorite paint. I personally use PPG epoxy primer over the top for the tooth required for body work.
If spraying, really really really clean the gun when you are done, or just throw it away if you are too lazy to clean the spray gun thoroughly as any POR15 that remains can not be dissolved. Also, dish-washing gloves go up the arms far enough to not get over on the arms when wearing a long sleeve shirt. You will also need to get the POR15 solvent for spraying.
Spraying small parts, I use the preval sprayers from the local auto parts stores, however I found that Menards and the hardware stores caries these sprayers for a lot less.
Always use a really good respirator when spraying (buy the best one you can). You do not want to breath in POR15 overspray as it will coat the inside of your lungs permanently.
