That looks nice. Tucks up real tight. Where did you get the bushings, or do you lathe them out yourself?
This isn't BX experience, but on my Ford hoe, I went from a 12" bucket (2.5 cuft) to a 36" bucket that holds 10 cuft level and 12-13-14 heaped. It has lots of digging power, but when swinging and fully extending to dump, the tractor can get tippy. But that's 1500-1800 pounds out 13' from the wheels at 90 degrees. Still, the concept should transfer. The extra weight could be "upsetting".
jb