Same on my 340, always a little fresh water around the prop shaft seal after heavy rains, there's never any drip trails or other wet spots that I can find. The bimini is only a year old and covers most of the cockpit and doesn't leak, so it may be coming from the swim platform lockers or running off the bimini and reaching the cockpit. It's on the list to look at, but there's always something else on the list that seems more important when I'm on the boat and not actually sailing. It's hard to remember to look the few times when it's raining hard and I'm actually at the boat, and spraying with a hose just doesn't reveal a leak.
So, I'm looking for some time saving leads or advice along with "ger123".