so for a 3mm endmill in acrylic I used:
feed - 1750mm/min
DOC - 10mm
plunge - 650mm/min
trocoidal stepover - 12.5%
trochoidal width - 50%
I then set up another 3mm endmill tool to do the finish passes with 1000mm/min feed and 10mm DOC
I used the same settings for a 6mm endmill too.