A few paint questions

[Dino]

So I'm getting 1 quart of SPI epoxy primer + 1 quart activator to do the engine bay, underside of the hood, and the hood hinges.  I will need a small amount of filler in the engine bay as I have some minor welding to do so I may end up spraying epoxy, do the filler work, and lay down more epoxy.  At a 1:1 ratio that will give me 2 quarts and should be plenty.  The question is how much topcoat do I need?  I'm going to use white epoxy and the topcoat will also be white so coverage should not be an issue.  I'm going with acrylic urethane but for this car, and since it's all underhood, I need a budget paint.  Which brand is recommended and how much shoukd I get?  Anything wrong with TCP Global's Restoration Shop paint?  I know how to paint but the HF hvlp is not exactly like a $500 gun so some paint will get lost.  I think a quart of paint mixed at a 4:1 ratio with activator should do it but I wanted to check with you guys first. 

An issue I have is that the car was painted in white lacquer decades ago, and I don't have the paint code. Besides yanking the door or trunk lid and getting it to a body shop, is there another way to find a match?  Does anyone sell paint chips?  We used to have these thick books in the body shop that had a few pages of just white chips with a hole in the center, that's all I would need to find a good match.  It may be under the hood, but two whites can be different like night and day so I want to get it as close as I can.