Thanks for your comments and photos of your work. My friend uses Lightburn at the makerspace, so I’m sure he’d stick with that. And, he tells me that he’s familiar with the necessary offset for the kerf width. And, clearly your experience (and of others) confirms the need for air assist.
I think the primary concern was whether the optical limits (inherent beam shape, etc. of the 40640 laser would allow these dimensions, and your results indicate that, while challenging, it should be possible.