Agreed FM - we have no real idea how this is going to play out, and how long it is going to take to play out.
My guess - there will be a day or two (tops) to review the Briefs and backing documents that each legal team has produced. Some time for arguments and rebuttals, perhaps a request by the Arbitrator that some piece information be clarified (if it is possible),...
If the hearing is going off today - it means all the preliminaries, conferences, legal discovery phase, and evidence to be used are there already.
According to FINRA rules (and they may be operating on slightly different rules in this case)