Welcome Newbie
Drips, drops and leaks.
Most will leak to varying degrees, very few won't and of the few that don't...most will leak eventually.
I feel that with care and prevention, you can stave this off or greatly reduce existing leaks.
I have been told "Never take the t-tops off if you don't want them to leak". IMO I feel this is bad advice. When you loosen or remove the t-tops, it allows the weatherstripping to breathe and relax, which will give a snugger fit when next installed.
*To begin with, you need to start with weatherstriping that is in good condition. I believe you mentioned dryrot, which will demand replacement. Some of the catalogs offer a 'weatherstrip kit' of all the pieces at a cheaper price than purchasing single pieces. The kit for my 78 was about $300. I also treat the weatherstrip after installation with silicone (dielectric -sp?- gel in a tube)
*I agree with the windshield fit, I have had mine reset (no good) and finally replaced, which helped immensely. Also check the fit of your windows against the weatherstripping and check to see if it is causing uneccesary wear when rolling up and down. (this is where the silicone comes in handy, allowing for a lubricated surface for the window to ride against)
I still carry a towel, but really haven't had to use it since the new weatherstripping and windshield were installed. I used to have a problem with rainwater being forced up under the metal pieces at the top of the windshield at hwy speed and leaking from either end of the interior molding. That appears to have been cured with the windshield reset, and I am driving through worse rain conditions here in GA than I ever experienced on the West coast.
Good luck with chasing down the drips!
Silver