So I've been pretty busy with life and getting the boat ready to launch, but I did do more leak investigatng over the past couple of weeks. The answer is: 99% of the leak was from the GPS puck on the rear quarter on the starboard side:

This was original to the commissioning of the boat in 2004, and was used by our old Raymarine C80 (RIP). At some point, I unmounted it and replaced an internal coin battery, and I thought I used 4200 or some such to bed it down, but whatever I used has now started to leak profusely (like a gallon per rainstorm).
In finding the leak, I initially taped plastic over the cockpit shower box, the engine panel, and the bilge blower exhaust, and still got about a gallon of water in the bilge the next rain. I then taped over the GPS puck, and have had virtually no water in the blind bilge since then. So I'll need to unmount the thing some time soon and either do a kludgy temporary repair (caulk or 4200), or figure out how the heck I'm going to plug 3 holes and finish off the gelcoat so it doesn't look terrible.

This was original to the commissioning of the boat in 2004, and was used by our old Raymarine C80 (RIP). At some point, I unmounted it and replaced an internal coin battery, and I thought I used 4200 or some such to bed it down, but whatever I used has now started to leak profusely (like a gallon per rainstorm).
In finding the leak, I initially taped plastic over the cockpit shower box, the engine panel, and the bilge blower exhaust, and still got about a gallon of water in the bilge the next rain. I then taped over the GPS puck, and have had virtually no water in the blind bilge since then. So I'll need to unmount the thing some time soon and either do a kludgy temporary repair (caulk or 4200), or figure out how the heck I'm going to plug 3 holes and finish off the gelcoat so it doesn't look terrible.