Has anyone corresponded with ampslab recently?

Glad you're enjoying the Lark SM.
It's really interesting to me as a non-designer how different the SM sounds compared to the original Lark: the modest changes to the cabinet and the revised crossover made a significant difference. I was able to compare the two designs as I made one of the SMs at a time. I repurposed the old cabinets for another project.

At the moment the SMs are in test boxes of the right size and configuration; proper cabinets will happen but I doubt whether my efforts will match the quality of the sound!

Geoff