Not long after I did my glass window conversion on my NA6, using the NB top and also new seals that came with the top, I was talking to NSW MX5 club member and he told me that he always rubbed vaseline into the window seals to help with the weather sealing and to help prevent any water leaks. Small water drops was always a problem only on the passenger side of the car and no matter what I adjusted I would always get the odd drop of water sliding down the inside of the pasenger window when I washed my MX5,
Anyway, I then remembered about using the vaseline on the window seals, so I tried this out. I noticed the vaseline soaked in very quickly, less than a day, so I put more on and noticed the same thing. The rubber window seals have soaked it all up. So I have just kept putting more on every few days.
What I noticed a week ago when I washed the car was that there were no water drops anymore.

Would rubbing the vaseline into the seals caused the seals to expand to their proper size and form a better seal against the window? Has anyone else noticed this? Strangely I have hardly used the vaseline on the hardtop window seals, but never have water leaks with the hardtop.