Well, my experience with Yotsuba is a bit strange… I started reading somewhere halfway through chapter 1 - aloud - in hinekidori’s old mumble server. Then some other chapter months later, about the air conditioner… Then about a year ago I began reading on my own, only got 10 or so pages in… but then in January and again in April, I read a lot while my parents were driving me on the highways in Michigan (as well as on the bus down to visit them)… Pretty quickly too, I might add… and a reasonable number of pages. For those done in the car with only my JED on my phone, I’m not sure of my translation 100% (as I was with the initial pages before), but I felt reasonably confident that I got the gist, at the very least. Wish I could better remember where I left off - since I don’t, I’m sort of re-reading to find my place again?
The thing is, with most of Genki I (finished up to Lesson 10) under your belt and about level 15 WK, and looking up anywhere from 20-50% of vocab and some hiragana grammar stuff per page (depending on the page) I do believe 10 pages a night is very doable - however, that depends on everyone’s amount of time they can spare in life, and so on. If there’s only one night a week they can work on it, 20 pages a week sounds completely reasonable. The first time I was reading (aloud) with hine-senpai, I was something like WK level 4, and hadn’t looked at Genki almost at all… (or maybe not yet!)… and I basically understood nothing, grammar-wise, aside from simple informal phrases I recognized from my many years of Japanese listening (*ahemanimewatchingcough*) experience. Having access to a good dictionary app on your phone certainly speeds things up. If most people can read it 2-3 nights a week, then 30-35 pages a week would be more than reasonable. The members who are at slightly higher reading levels could likely complete that all in one go, and then be available to help with translation/grammar.
So, anywhere from 20-30 pages a week is probably what I would recommend, seeing some of the lower levels of this group - at least for the first chapter of volume 1 (which is 50+ pages - whoever said that is correct). Then we could speed it up and add another 10-20 pages in the subsequent weeks.