To expand on what @dklgood and @linefeed are saying (I think they’re both exactly right): Generally the best way to cut things[1] is “fast and hot” meaning you want to blast what you’re cutting at full power and move as quickly as you can while cutting. This logic doesn’t work too well with really thin materials, the laser tends to overburn too much even at high speeds.
If I were you: I would pick a very fast speed (450 or so) and then do a material test to back into how much power it takes to get through it, and use the very lowest power setting you can while still getting clean cuts.
My testing method is laid out here in #6:
As for the idea that it’s “not suitable”, that may be true… but until you do a test like I described you won’t know for sure. Some plastics are definitely not appropriate – they melt too much or are exceptionally flammable or contain chemicals that can damage your Glowforge.
You’re in the clear about the chemicals with acetate, now you just need to see if you can find a way to cut it reliably and safely.
There are exceptions to this logic but I won’t get into that here. This logic holds for most materials at ~1/8" thickness. ↩︎