Water leaking in after heavy rain..

After and during heavy rain, water leaks in and drips on to my seats in my Mk1 Cabby. I know I need a new roof to wind seal as it's peeling away from the sides. But the water seems to be coming in via in the inside of the roof to window  seals. Between them and the j roof clip. I wonder if it traveling between the seals and finding a way in, as it doesn't do it in light rain or a quick shower. It's got to be constant rain. It also drops on my knee during driving. I have leather seats so they are easy to wipe but I don't want it the carpet or floor ruining.. 
could it be just a new top roof seal I need or some other seals too? 

Every thing I know about leaky tops is here.

      Leaky Car Syndrome fixes:

Another Leaky Knee Fix.
http://www.toplessrabb…viewtopic.php?f=41&t=2737

Swimming Pool in Front Seats.
http://www.toplessrabb…viewtopic.php?f=41&t=2853

Where is my top leaking.
http://www.toplessrabb…viewtopic.php?f=41&t=2655

Where is my trunk leaking.
http://volkswagenowner…Where-is-my-Trunk-Leaking


Why are my feet Getting wet, all I did was change the antenna.(Drip Stop Loop)
http://volkswagenowner…-just-changed-the-antenna…..

After three years of mild leaking I finally found an unlikely culprit on my 83 sunroofed gti. 

Water or at least moisture was travelling up the sunroof run off channel (front to back channel) and found a gap between there and the roof skin, somehow crept over there to where the door light area is and then start spreading across the inner roof until it would drip on the seats. 

Sealing from out and in cured it immediately 

Do you still have the plastic seals external to the main roof seals.  These cover the joint in the door seal and roof to glass seal. .. 1 of my cars leaks similar place. But the plastic is hard to find or replace. It's available but sometimes has lead time