Considering how VLM can (hopefully) print support material and lower Z heights result in faster prints, it makes more sense to priorities less frequent topups of the resin cartridges than a couple of extra centimetres of Z height. As long as I can theoretically print an entire half of #Teti [gd0022] (256mm) or tile cover for the #T^2 Tiles [gd0095], (260mm ish) I'm fine.

To get a rough estimate, I just threw the model with a cutout for where the peristatic pumps will be into Cura and sliced 4mm walls and 999 walls, and then take away the latter from the former to get the material contained inside. For a 48mm high cartridge, I get about 1700g and for 37mm it's ~1300g. That disparity increases when opting for a double height cartridge. 

Since there's a few other walls that need to be inside the cartridge, I'm expecting the 37mm cartridge to be around 1000 - 1100g and the 48mm one being 1500g. The double stacked for 48mm would be something closer to 3200g.

My main concern now is that they'd be something like 2.3 * 5 + 0.5 = 12kg of cantilevered mass. It's cantilevered since the sides are the ony way to install the cartridges so I need to be able to slide them in and out. I'd have to see if the quad 9H carriages can take it and look into a very thick belt with the pulley mounted onto the 42.4mm tube.