I remember searching for this fix awhile back and didn't really find what i was looking for but i fixed my 89 crx hf bad hatch water leak that was dripping on the back speakers from the gas struts. Since i didn't have a sunroof it wasn't that (Most think it is from drain lines and hatch weather stripping), so first i took off the hatch and pulled the plastics back.. found rusted water trails etc. basically sealed all crackes, bondod a big rust hole, nuetalized all rust and sealed any holes on top between the hatch and the roof, any thing that could leak. Lastly sealed the bottom of the hatch brackets before i bolted it back on(for this i used ULTRA GREY RTV). Also gently pulled the black strips of metal rubber off the roof on both edges and cleaned and sealed in there as well. be gentle and use a flatblade and lightly pry up starting from rear of the strip(it will bend be carful).(FOR ALL SEALING USED a universal white seam sealer, comes in black as well, and you can get it at NAPA. You'll need a caulk gun to dispense it to) if you have holes from rust you will need body filler too.
So basically my car now is as tight as a drum no water no nothing and im as happy as can be, hope this helps sombody out there.