I would think that with wetplate the biggest issue would be the ability to pour a larger plate, but I'm not a wetplate photographer myself, so I would be interested to hear from the wetplate shooters on that.
Honestly, I found it was easier to pour the larger plates once you had some practice. 11x14 was easier than 8x10 which was easier than 4x5. Now I don't know about Zebra and his 20x24's though!
Let's see what I've got in the magic trash can for Mateo!