My intention was to achieve a fine, but quite gritty finish: I played with the pressure/distance with the black until I settled on something ~60 PSI (I'll check next time I run it) and I've left it set there since. Higher pressure will definitely put it down finer. I will also say that the texture varies based a lot on technique: the further back the gun the finer the spray; the thinner your coats grittier it stays. I think that perhaps another reason my 2 colors differ in texture (besides a possible viscosity difference) is that the primer I used was very similar in color to the grey, and I likely added a bit more on the first coat trying to adjust for lower visual feedback.
The shutz gun is not the most precise tool. That said, I'd take it any day over a roller given my desired result. While I've heard great things about Monstaliner, the only roll-on jobs I've seen are Herculiner, and they've all (obviously) looked awful.
The quality of the U-Pol products is really there: at one point we ran out of the U-Pol primer and ran to O'Reilly's in a pinch... The dupli-color stuff they sold was such dog ******** by comparison that we stopped, waited, and sanded most of it off. Now that the black rocker panels have had a week to cure to full hardness, we were able to rest the edges of the doors on the driveway (albeit gently) with zero concern. We originally tested it on our grille a few months back, and fell in love with the product then.
I also have nothing against Monstaliner. If you're looking to roll on a liner, they're almost certainly the way to go.