The Big Ten schools have such large student sizes so may vary per school for how they handle. For mine, we had and A, B, and C team (A and B were competitive travel teams) that each comprised of ~30 players. For the A team, looking around 7-10 UTR (1-3 star level recruits) and 5-7 UTR (0-1 star level recruits) for the B.
The club was student-run and had it's own e-board of a president, VP, secretary, treasurer, and social chairs. I operated as secretary my junior year and VP my senior year so can tell more about the that experience too. Definitely a lot of work, but also very rewarding
The A team practiced 3 times a week, the B team 2 times, and the C once a week. We didn't get to practice at the varsity team facilities and had to go to some indoor courts more on the outskirts of campus during off peak times so this was pretty much the max that we could do.
As for attendance, was really dependent on the year. Some players inevitably drop off when joining sororities/fraternities. My freshman year, almost everyone dropped off due to poor leadership lol. My next three years were much better with most players showing up to at least 1 practice a week. The success of the club attendance is very dependent on the quality of leadership and the culture they establish early on