If the team has mostly lower levels, and as you state it is a small team, I would not do a booster club. It is more trouble than it is worth. Negative, 1) as bookworm states, you will be hitting the same people; 2) if you have a non-profit organization, you will need to provide for everyone, even those that don't contribute; 3) it can leave the contributors feeling slighted; 3) fundraising is not always successful. Many bring in very little. In house meets bring in the most money. But you don't even have that. Honestly, There are just too many charities and not enough funds. I have 4 active kids and have been a member of many booster clubs. I cn honestly say, I've always put in more time and money than I get. At a minimum, I break even monetarily, but I come out way in the negative with the time and effort I put in. The only positive I can see is the sense of community and helping each other out, which has its own benefit. The athletes also enjoy working together for a common goal outside of the gym, field, dance studio, etc.
Booster clubs can be beneficial for larger groups and higher level gymnasts. L9 and L10s tend to travel more for meets and then there is regionals and nationals. At these levels it can be expensive. So members feel more inclined to help out. I would first find out how many families would be interested in setting up a booster club before you spend more time. You should give them an idea on the commitment involved. Provide them with the following information 1) amount of membership dues; 2) goals of the booster club, i.e. pay for competition Leo's, meet fees, coaches fees, clinics, etc. 3) let them know how you plan accomplish those goals, i.e., how many fundraisers will be needed, commitment from each family, etc. The trick I found is you have to be as transparent to the families as possible to,avoid less complications as possible.