Wouldnt the 1.5" be better for really small details, than the 2" and 3"? Also i dont see a 3" lens, not for CO2 atleast. I see a 1.5, 2.0 (a 2.0 clearance), 2.5, 4.0" . 2.85" is for flexx and 3.2" is for the fiber laser.
But then again, you guys are the experts and im only seeking advice