Welcome to another Cobb ! My 1070 has weighted rear tires which seems to help. My tires are the R1s (ag type) and on a side hill pulling a mower it will slide sideways before it begins to feel tippy. I use the individual brake pedals to keep in in line. Yes its a bigger tractor with a larger motor and tires, but your answer will depend on a lot of variables, including where the bucket rides, tire spread and pressure, canopy, fuel tank level, and obviously where the BH is positioned (and how much YOU weigh).
To get a rough estimate, you could get a platform scale, an inclinometer and a jack. Make a plot of the scale weight vs angle and project the angle to a zero weight estimate. Then back it off 10% for a safety margin. Crude but effective. Then measure the sidehill angle you want to traverse.