Dredging this up…
My fuel consumption issue kept coming back intermittently. I did find that there was an issue where the tip of the cable controlling the choke could get snagged under a post and possibly not let it close all the way, but the issue persisted despite that fix. In the Rotax maintenance course, my instructor mentioned to be careful with the carb float bowls, as they're made of zinc and can be bent surprisingly easily.
I pulled both float bowls and the pins were visibly bent outwards, likely from a too-long piece of hose placed underneath the bowls on the drip tray for vibration dampening purposes (per KAI).
Compared to new bowls, one had the pins spread by 2mm, the other almost 3mm, and the brass guide pins looked quite shiny in spots. Marvel-Schebler epoxy floats were installed, and the tops/bottoms of the floats had a fair amount of brass residue on them.
Installed new bowls (which came with a new design and grey coating) and put new, stock Rotax floats in. So far so good.