How about writing to the directors and urging them to settle, out of court.  Would save some of the potential costs you're concerned about  Have you tried to contact them?  Do you know any of those board members?  See how far you get with that approach. 

I happen to think the board is going to lose the case.  Their side seems very weak, basing much of their views, on the word "should".  So it seems a wise move to settle the case, pre-trial, out of court.

On the other hand, if you get no response from the board, this will indicate they are dug in, refusing to budge, and sustaining a hardened line against the 800+ members.  Slapping those members in their faces.   Resisting restraints over the board's spending powers, and grabbing legal expense funds out of members pockets to sustain their spending powers.

Tom