Have just watched the videos in the begin here section and wondered if you consider the Charles Bargue plates as a useful source for practising drawing accurate shapes periodically (as you advised).
I don’t have a lot of drawing time and would rather start smaller than the bust you demonstrated with.
It’s been a while since I downloaded the book and I’m not sure which site I used. Just now I typed ‘charles bargue drawing course pdf free download’ in Google and got several hits. Good luck!