I asked Tom about this a few years ago when it was brought up about the melges 24s. He told me in an email:

"As long as the sails fit within the dimensions of the largest rated sails and would meet the legal definition for that sail category you can carry as many jibs/genoas and spinnakers as you desire.

Tom Beery"

You can have smaller spinnakers that are flat but must measure in as a spinnaker (greater to 75% mid girth).