Maybe somebody else will chime in that loads super-b's with one, but I think 45 tonne would be very a full cart of canola.
Run one for 4 years now. Great Cart! You will only load about 1850 bu of canola under normal conditions. Can't get 100,000 lb loads.
Barley loads are extremely heaped and topped off to get a full load. Can't do it moving either, but it's a lot closer. 1950 bu or so in good weight. In super heavy barley you might get the 100000 lbs, but not normally.
Most of the time, we just heap to the max on the fly and send a super b load. Can't do that in peas or wheat though, will be way over. For barley and canola it's close enough, unless you're going a long ways, or sending a trucker instead of hauling yourself.
I think if there was an additional 6" of topper, it would work for all. In case you are listening Elmers....