Regard your comment on how the burner is lower on the micro, I'm wondering if that's the possible cause of CO, would it be possible to unscrew the stem from a PR, cut some off, retap the thread and drill the air hole, and achieve the same thing? Would make the burner lower and easier to shield from wind too.

I don't know enough about adjusting the air/fuel and lack the equipment to drill it, so I can't try it.