Try the guys at 2nd Wind in Attadale. They're South of River (SoR) but you can sail on the river there out of melville or head down to leighton beach just north of freo for some ocean B+J or wave sailing.
What are your chances? Last year I sailed 4 times in May. There seem to be more fronts coming through this year but they haven't established a pattern yet. I'd say your chances are 1 in 7 of a sail on any given day, if you are here for a couple of days your chances will go up.
I agree that 2nd wind in Attadale is the best place to hire gear at this time of year.
