Not at the boat right now but it seems to me I ran some wiring through here decades ago. This assumes the hard ceiling head hasn't changed much between my1999 and your 2004 :
A closer shot of the entrance :
You want to open that up to ensure it's ultimately dry up there. You will not access that area as all work is done on the exterior of the cabin roof.
Are you thinking the leak is through one of the machine screw hole(s) in the genoa track ? I'm guessing that anything fixed to the cabin roof is machine screwed into threaded aluminum backing plate(s) on the underside of the cabin roof and just above the hard ceiling.
Slow picky job but can be done if that's the source of water ingress into your head. Maybe into your boat's head too

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