I got side tracked and put to much water in it the other day and water went every where...(gave me bad square tank flash backs)...In all fairness I never checked the adjustment on the float to see if it was in the right spot but one would think that it should of shut off before the water came out of the top
IMHO this is a poor choice float to be specified for a moving vehicle application on a LARGE tank. While waterbox application sloshing seems to be minimal, the wave action in a large tank can be severe.
My dad and I built a large stainless steel combo solution and recovery tank for one of our Banes over twenty years ago. We used a very simple float shutoff enclosed in a perforated 4" PVC pipe mounted vertically. It worked flawlessly. I still have it.