While having a decent turnout for the event itself would obviously be good – surely it is also worth trying to encourage turnout between now and then.
Rather than having a predetermined number of boats from the off [other than an overall maximum because of venue constraints] how about having a minimum event attendance [eg 3 of the series or something] in what would then become the qualifying year. To just be able to show up without a bit of activity beforehand on the circuit seems a bit feeble – and while we obviously do this for entertainment we also do it for the competition.