Islander May 23-28 over Memorial Day weekend - got a few questions. Thanks!

Newbie here, looking forward to our first cruise. Any idea how full the Islander out of Tampa has been recently? Curious because I was checking out available cabins by doing a booking and seeing so many cabins in all different classes still available.

Interested in upgrading and wonder when's the best time - just keep checking and do it right before the cruise? Still seeing high costs for upgrading on Cruise Control. Thanks!