I did some 1/8” black acetal and tried doing a double pass at power 100 speed 30 and single at speed 15. Both worked well and I don’t see much difference in the cut quality. One thing that did stand out was that the double pass had a lot more white debris around the cut area similar to smoke stains on wood. I think this is because the debris can’t go out the back and has to come back through the top of the cut since it’s just a trough for the first part of a double pass cut.
Here is the double pass:
And here is the single pass:
I made these for my nephew and nieces