Do either of these tub provide more floor space than the other? I know the dimensions are different but they are both 11qt…
Whichever one is larger in length and/or width will have more floor space.
Going by the listed specs for both, the VE tubs are going to give you more floor space.
Can I run one thermostat for a stacked ve6 or would that require a 300x2 at minimum?
You would have to test it. I would think since they are different, you won’t get the same outcome and will need to have them on their own thermostat. Or get one that can control more then one source. They make then for 1, 2, 4, 6 separate controls. Each has its own probe and outlet. If the bottoms are different thickness or if the height is different (if using from the top) then you won’t get the same temps from one controller output.
Same material/same rack just 6 levels so 12 total. The ve300x2 probably would be needed on that then. What thermostats work with 3-6 probes? Herpstat?
Herpstat has 4 and 6 control units. Looks like “the bean farm” has them.