Hey hey heya! Sorry for the long wait! I've wanted to reply to every comment thoughtfully, and your comment on the single file bit was the first feedback I've heard about it. I've sort of fretted about that decision (though it's paid off well for me), and I wanted to say I can't express how much anxiety that one small compliment has relieved for me. Not that everyone will like it, but that it's indeed a good idea.

As far as speed goes, I've filled out a few good comments about a "what's next" here with Bram in my comment to them. There's also a corresponding Reddit thread that I've been frantically corresponding on, but most of that is more historical-and-hyperparameter focused! (https://www.reddit.com/r/MachineLearning/comments/10op6va/r_...)