You are thinking the same things I was concerned about. My pastures are not level. They are uneven and hilly, so I am concerned about the water shifting on a hill.
I may have to go with a smaller sprayer.... or I could use this as an excuse to get a bigger tractor. HaHa.
It depends on how much incline you have on your hills. But it is well that you have factored this in and thought about it. Safety is the primary concern.
Going UP a significant incline you have gravity working against the weight of the tractor and that weight begins to shift to the rear. So in an extreme situation....it might be possible to lift the front end if you were to apply too much throttle. Naturally, you want to keep your load (rear mounted equipment) as low on the 3 point as possible.
Going DOWN an incline....you now have that weight 'pushing' you and you'd want to be sure you have adequate traction to keep from skidding down hill (using only engine braking). These are extreme scenarios you understand.
Operating off camber (side hill) with tractors of narrow rear wheel width is always a potentially dangerous situation and when you have a liquid load that can suddenly shift (drop a tire off in a hole) bad things can happen quickly. The more liquid you use, the less the weight but it also can move more.
I'm not saying you can't safely navigate your property with the rig you are considering. I don't have pics to go by, but do consider all aspects of it, as you seem to be doing.
IF you decide that a 60 gallon vessel is too much for your tractor then you might consider a smaller unit. I wouldn't half fill a 60 gallon unit as it will only 'slosh' more than full 30-40 gallon unit and cost more.
Just be careful.
