Acetone will flash off too quick, especially when atomized and blown through an airbrush, so it is not a good thinner for SB Coat paint. It can also promote blushing which is moisture condensation on the paint which can lead to a matte finish look. It is fine to use for clean up as long as the paint isnt dry. Acetone is cheap and more readily available than most other solvents.
Adding the pearl/mica powder to the Clear 3000 is fine. Looking at your mix ratio you have about 25% mica in the paint, which is a lot of solids. This may be contributing to webbing. Try cutting it in half to around 10-15%, it should still be effective and probably spray better, even if you have to do two coats. An addition of a little Retarder 3002 wont hurt either, maybe 10-20% of the total paint mix.
I would use SB Coat Retarder 3002 or SB Coat Thinner 3001 for thinning or correcting excessive cob-webbing. Webs in your exhaust filter and around your work area are normal. Filters are consumable and do need to be replaced over time. Webbing as a concern is when it happens straight out of the airbrush. This means the paint is literally drying instantly as it leaves the airbrush and therefore you not likely to get a good bond to the bait.
Im not sure how the above recommended homemade cleaner will work for SB Coat when its already dried. SB Coat is a vinyl and not an acrylic. For dried SB Coat in your airbrush SB Coat Thinner 3001 will do the trick, it is more aggressive than the Retarder 3002.