I agree with SX not going to Concillation risks your chance of even getting an Adjudication hearing because you have to state whether you have been to concillation on the Adj application and an Adj could reject your request if you haven’t.
Also the time scale is against your (it’s 35 years ago) and I also don’t know whether a statue of limitations applies to bylaws.
A safer argument would be that the EC is planning on spending OC funds on exclusive use areas which should be the reasponsibility of the owners that benefit from the exclusive use areas.
Whatever you decide put forward as many arguments as possible to the Adjudicator for the bylaw to be overturned or the spending to be refused because you only need the Adj to find in your favour on one of the points for you to win.