Here is my thought, but I need some feedback. We have 24 total girls. What if we split into three teams? Eight on a team falls right into the sweet spot for a club team.
We would have the four 4th graders and four 5th graders playing together. They would be playing 12's as much as possible using the volleylite.
Then we would split the 12 6th graders into six on a team and add two 5th graders to each team. I want the 6th graders to play with the regular ball. I want them ready for 7th grade volleyball. It would not hurt the 5th graders as we start 6th grade volleyball next season.