He did say that he was first attracted to plates through wet plate collodion but then developed his own process.
You can coat your own plates with Liquid Light. They're going to react a lot like wet plate when it comes to exposure but don't need to be wet to record information.
From looking at the video, the plates he uses don't look like wetplate. From memory, wetplate is a lot less contrasty looking and not as crisp a black.
So I'm going towards the liquid light on glass plates position.
I did notice on his camera that he has a sticker giving shutter speeds and adjustments for T-Max.
