Wing, I have a 34' Irwin Citation that has cockpit sole access to the diesel that is supposed to be simply fastened at four corners (hasn't been for years). Also have locker access starboard to #2 battery bank. Both are scuppered to drain water. Admiral and I are re-installing the fasteners for the sole access this spring as I've been sweating a knockdown. But, as for the locker, it is latched so I don't really consider that a real worry. That said, I probably don't have some of the same conditions as you do in SoCal.
Pretty boat!
Mark