I already know what a Kubota L4240 with a 6ft bushhog will do on steep ground. You can try it and we will decide what you think when you hit the bottom, either on its wheels or on its top. I dont hold out much hope for the L3200 either.
The primary factor influencing tractor stability is the spread/stance of the rear wheels/tires. The Kubota L4240 has rear tire/wheel spread adjustment of 12" as a standard feature with both R1/ag or R4/industrial tires. Did you set the wheels wide on the L4240?
The second factor is wheel ballast
. Loading tires 50% to 75% with ballast improves tractor stability by lowering the center-of-gravity. Were the L4240 rear wheels ballasted with liquid or wheel weights?
Third stability factor is ground clearance. Less ground clearance is better than more for stability. R1/ag tires increase ground clearance over R4/industrial tires.
What tires did you have on the L4240?
The Three Point Hitch tractor has been marketed in the USA since 1939. Patents on the Three Point Hitch and TPH hydraulic controls expired in 1955. Since 1955 (66 years) all traditional compact tractors have been designed and produced around the Ferguson Three Point Hitch, worldwide.
The Three Point Hitch tractor design is generic.
When T-B-N correspondents correlate any TPH tractor brand directly with stability it invites skepticism.
Best tractors I have found for wood work are the older Massy Ferguson models, (235, 245's). It just seems to me they are more stable and heavier weight wise.
Ground clearance of MF245 (1976-1983) is 9.4
Weight, diesel, 4,050 pounds bare tractor.