Leak under front of dash - vent window?

The canvas door stops on my passenger side were ripped when I bought the van so I had removed them. I finally scored a set on eBay a few months back and after installing them, I now have what appears to be a slow drip that lands right on the canvas stops and then drips to the carpet below.

If I look under the dash, it appears the leak is coming from the front corner, but it's slow enough where I can't figure out the source. I don't see any rust on the outside, and the windshield seal was changed a few years back.

I'm wondering if it could be the seals around my door or vent window that are causing the leak. They're mostly intact, but old and brittle, especially around the front top of the doors. Anyone seen anything like this before?

Either that or the windshield gasket would be my guess.

The only reason I didn't suspect the windshield gasket is because it's new, while the gaskets on the door are either original or decades old.

I would double check to ensure all of the edges of the windshield gasket are nice and flush. Perhaps run a hose around all of the edges to confirm. Just my .02cents

Unfortunately this is the slowest leak I have ever seen. I tried a hose around everything and couldn't get a leak. I sat in the van during a heavy rain, and I got 1 drop every 3-5 minutes. Given that, it's really hard to isolate the source.

I replaced my windowing gaskets with Steele Rubber Products and the fit and finish are excellent.

I was able to score a NOS windshield gasket, so the fit and finish were obviously also excellent.

Oh, and thanks, I'm now looking at the Steele Rubber for the door/window gaskets.