Richard -- Each member can open their own Dropbox account and thereby pay for only the space they use. Then the Club can open a free DropBox account. Now, each member can share a folder with the club's Dropbox which is open on the observatory computer. The club adds each member's folder to the club's observatory Dropbox. Those added folders expose the space being paid for by each member. If the name of the folder matches the ACP login username of the member, then the ImageFileConfig file/folder renaming can be just one entry shared by all because one of the substitution tokens is the username. If a member wants something specific/special for file naming then he will need his own line in ImageFileConfig.

The above is probably confusing. Whoever is responsible for the configuration of ACP for the club can get hold of me and I can help by phone.