You know, my first real experiences trying to do super smooth characters was a "Breaking Bad" cartoon project my brother and I embarked on years back. I about went crazy sanding and priming literally hundreds of parts (At the time I just used Krylon) and then sanding again to make sure everything was smooth on multiple copies of the sculptures....It was rough and messy.
Now what I do is spray the sculpture with an acrylic matte clear coat, and after that dries I hit it with some Testor's Dullcote to give it some tooth. It's a life saver! Now I can just sand the piece ONCE! WHEW..... I've been considering making a limited run of each of these tiny Jessicas, so it's more appealing to think I can get by only having to sand things once on each copy.
When I start painting, though, I embrace some brush strokes showing up. I paint everything with very thin coats by small brush. If anything builds up too much I sand it down, but mostly I like for that hand-made quality to show in the final work. That's not something most people want, I guess, but I'm resistant to "perfection"... When looking close at things, I LOVE to see the process.
Thanks for the tip about Aztec, I'm going to look into that brand.