Thanks for all the feedback so far, really appreciate it.
I've pushed an update for Soda Light that now includes both square and curved tabs. The tab style can be toggled via a user setting. Square remains the default at the moment, but to opt into using the curved tabs, add the following line to your "Settings - User" file:
I'm still looking for an elegant way to handle custom settings. I'd like to use more than just booleans, and be able to group together all Soda settings under a single namespace rather than introduce a bunch of top level custom flags that may conflict with each other. If you know how to do that in a way that can be then read by a theme, please let me know
Here's a screenshot of the two tab styles for Soda Light: