Hi @sgibson91 @JessicaS11! I think the key here is seperating the computational environment versus content (whether they are on separate branches, or separate repos) as described in this forum post Tip: speed up Binder launches by pulling github content in a Binder link with nbgitpuller.
I suppose this is still considered ‘advanced’ usage. Plus it only works if your environment has nbgitpuller installed. In any case, I think the link generator on the nbgitpuller docs is really handy! Perhaps it’s worth linking to here https://mybinder.readthedocs.io/en/latest/using.html ?