John,
The moorings are a first come first serve basis (radio the harbor master as you enter the harbor, or approach a harbor patrol boat in front of the harbor), unless you own the mooring, then you need to reserve the mooring at least 24 hrs in advance..... During the off season, the harbor patrol will sometime allow individuals to use a mooring for a few hours at no charge. It all depends on the officer and his discretion.
I would expect this weekend to be fairly busy....the tournament, along with the last weekend before the holiday weekend...so many who wish to avoid the rift raft of Memorial day will come this weekend instead.
You can do one of three things...
rent the mooring for two days and pay the $22-$24 per day fee for a boat 25 feet or less, and fish and not have to worry or stress over getting a mooring, or you can rent one Saturday, and chance it Sunday (most likely one will open up). Or you can chance it and hope one is available for a a few hours and you get a officer that is easy going.
If you gamble and loose, i am sure you could find a fellow angler who would let you side tie (you still need to get the harbor patrols permission and pay the same fee's).
Or you could always find a nice cove and anchor up for the night, and fish through the night....bettering your chances for a prize fish
Good luck to you this weekend...hope you get a nice toad wsb or butt.