Okay, so here's the update to the few methods I tried.
First is the sprayable fabric paint.
I don't even want to talk about it, but I will. It was the worst. I got this paint from Walmart and it doesn't even work right. It constantly goes from spray, to stream, back to spray. I couldn't get a consistent spread and it was super liquidy. It ended up being a red puddle, and as soon as I got the screen cleaned off, I threw everything away and washed my hands. Don't use this method.
Next was puff paint.
I don't have a picture of the process, but I squeezed some paint into a cup, and brushed it on. It started out pretty good. I pulled the screen off and hung the piece of fabric to dry. I had heard about puff paint bleeding if you don't dry it immediately, and that's what happen. It was probably a cross between the fabric being to thin and the amount of puff paint I pushed into the fabric, but I didn't dry it fast enough, and it seemed to keep soaking into the spandex. The checker pattern ended up being pretty hard to see and the fabric feels stiff. Just infused with paint and no longer stretchy. Kind of disappointing.
I think if it was put on very thin for a first layer, put under a fan or flash dryer, then given a second coat and dried again that would be better.
The third, and actually the best looking, was the spray paint. I just used some Krylon Fusion I had.
I did about 3-4 coats of red, which just disappeared into the spandex. When I was done with the red, I tried out the brown Krylon I had for fun. Interesting to see the shading. I liked that the paint wasn't super wet, so I could wait a couple minutes between layers and know it would stay put with no bleeding. When all was said and done, the spandex lost a
little flex, but for the most part, unaffected. The pattern is nice, too, for a subtle change to plain red. But once you get close to the fabric, there's no texture. That would be enough to turn some people off.
All in all, I'd say to spend the money for some of the nice textured fabrics that are posted in any of the Deadpool threads. The spandex was $2 for 1x2 yards, the spray paint is about $5, and the screen is $0-$10. It's a lot cheaper, but only if your time is worthless. The amount of time that goes into filling the screen takes a while, for sure.
I hope that helps someone.