Last fall my son's school had about 25 kids on JV and 22 on V.
In the spring there were 21 on varsity, and a couple of JV kids who were called up at the end of the season. The JV team had 25 kids in the spring. One didn't end up playing due to injury (my son), and one V player had to come down in the middle of the season due to a state association ruling.
25 is a lot to me, but the JV team only played Saturday double-headers, so everybody got some playing time each week.