We are a similar sized team to the OP (somewhere around 36 on our competition team this year)
As our application process currently stands, there are two parts: club season and competition season. Club season is open application, so anyone can come to learn or get an idea of how the team runs; there's only a few forms, and it runs from the beginning of the school year to Christmas Break.
At the beginning of club season, we start keeping track of hours: to apply to the competition team, one has to contribute a minimum of 40 hours during the club season (at least 10 of which need to be outreach). If we aren't productive (learning or helping), those hours do not count, and can be removed from the log. There's then a formal written application to the competition team.
Once on the competition team, we require a minimum of 80 hours during the build season to attend the competitions, judged by the same criteria as during the club season, and there's benchmarks within the season that need to be met to stay on the team.
People that aren't super interested tend to leave during club season
