So you´re doing both then? sanding plus gas polishing?
Do you use a polishing disc for the sanding or rather sanding paper?
I know it´s been a while since my last post on this topic, but I´ve been busy 
though I got a small update for those interested in Acrylic cutting.
due to the above advice, I´ve added a finishing pass as an experiment. I landed using the following parameters for now;
3mm 1 Flute Upcut bit
6mm Z+
60° plunge rate
20mm/s feedrate
2mm plunge feedrate
6mm Z+ finishing pass
10mm/s feedrate finishing pass
2mm plunge feedrate finishing pass
30% Stepover
20% Trochoidal stepover
50% Trochoidal width
0,05mm Trochoidal oscillation
On my first examples, setting the Katsu Router on speed setting 2, I got exactly the same results as my previous setting without finishing pass. So that´s with small random cracks in the edges (tear out I belive it might be called?).
Throttling down the speed setting to setting 1, these cracks have been eliminated by 99%. I believe it´s not perfect because of small machine movements. It seems hard for the machine to follow the same path, especially visible when carving text. Wonder if an LR3 might be better at this.
The edge result is like 20% more transparent with my new settings then before, although I must say it depends on what edge you´re looking at. All 4 sides have a different look which is odd for a beginner like me:)
It´s on my todo list to buy a specific acrylic 1 flute upcut bit. So hope to test this in few weeks to see the difference between dedicated acrylic cutters and regular single cutters, but first I need to find a 3mm collet for my katsu, so the new flute will fit the machine as the shank is 3 or 6mm not 3,175.