I'm currently using a Starboard 11'2" for downwinders with the standard drake fin that comes with it. Yesterday doing a downwinder in 25knotts and decent swell I found the board often spinning out. Would a larger fin help when doing downwinders? I have a large Jimmy Lewis fin that originally came off an 11+ foot cruiser, would this be a better downwind option for the 11'2"?
These are the 2 fins that I have

I'm hoping to get out for a paddle sometime wednesday. Anyone else keen?
Looks like southerly wind allday, perhaps a downwinder somewhere along the coast.