Figured I'd update this.
Along the way I bought parts here and there. I've had all the parts now since last summer, but had been wanting to save some cash to send it out for an XM gray finish from US Anodizing. I've finally realized that just isn't going to happen because of money, so I started looking at alternatives. I picked up a $12 rattle can of Brownells Aluma-Hyde II, which is a spray-on epoxy finish. It also doesn't require oven curing like Duracoat, Cerakote or Brownell's Gun-Kote....though you can do so at low temp just to speed up the curing. I've read posts of guys curing it at 350* like other finishes and it ruining it.....most commonly by making it really glossy, or at worst burning the color.
I spray my PSA lower receiver, external lower parts, and buffer tube on Wednesday. With the understanding that it is a $12 finish, I'm pretty damn happy. It's not an exact match, but looks a whole lot better than a mismatched black lower. It was fairly easy, though I did get some imperfections on the right side of the lower when I tried spraying the 2nd coat without first spraying just for the sake of cleaning out the nozzle, and it spitted some. The rest of the lower and all other parts came out perfect with a matte finish. I did 3 light coats, 10 minutes apart, letting the spray mist the parts. Going heavier and doing thick coats will result in a glossy finish, from what I can learn by looking at various examples across the gunternet.
Just waiting until Wednesday to assemble the lower. Just want to make sure it's fully cured.
Aluma-Hyde is pretty easy to use, and cheap. I'd totally use it to refinish some other beater pieces for fun. Supposedly it's more durable and more solvent-friendly than just Krylon or engine paint, but not as durable as a "real" bake-on finish. Fair compromise. Also, for what it's worth, it doesn't feel like an epoxy finish, with how some of them feel gummy, plastic like, ect....it still feels like a piece of anodized aluminum, which is nice.