EDIT: Dumb question, but for scheduling purposes, what's an order-of-magnitude estimate for a block of 8 questions? Is this like a weekend-hackable thing, part-time during the week, month sabbatical, or what?
Regarding time commitments: it is hugely variable, mostly I think because different people put different priorities on finishing. The first set should go very quickly.
I would love it if these took a month of work, but people have gotten through them in a couple days, and there's some delay built in there because of email.
If I were working on them full time I'm confident I could get as far as I am now (mostly finished the third set) in about a week.