Is there a paint expert in the house?

[Rooster's82]

I have just made arrangements to start painting my truck; it will be done over the next few weekends. Body work and bondo this weekend, scuff and primer next and then paint 3 weeks from now. I will have access to a booth and paint gun, and an amateur painter.

I have decided to go with a gun metal/charcoal gray, and I want to add some silver/metallic fleck to it. This is my first paint job and I don't know jack about paint. I am also poor.

So my question are:

What paint do I get the best bang for my buck?

I want a dark gray, how dark can I go before all the imperfections start showing up? I have to do a fair amount of body work on one side.

How much silver/metal fleck can I add before it looks like crap...I really want it to sparkle. Can I add fleck to any paint?