Biplanes can be tricky. I would say it all depends on what your expectations are. Having some aileron differential is beneficial to eliminate adverse yaw. With an Ultimate, you won’t need much. Personally I’m not a fan of the 0-0-0 setup. Most are fooled into thinking that it lend the airplane to fly inverted the same as upright. Not exactly accurate. With a reasonable CG the 0-0-0 setup you need to force the wing(s) into a positive AOA to produce lift with some up trim. That works fine for upright flight but you can imagine what it does for inverted flight but it will also adversely affect knife edge and up lines. My preference on aerobatic biplanes is 1 degree positive incidence on the bottom wing with engine and stab at zero. The 0-0-0 setup works well if you are running the CG fairly aft. I also set up all 4 ailerons with the same throw and differential. I in fact accidentally had more throw on the bottom once and could not get a rolling combination to look good no matter what. After I got home and started measuring things I found and corrected the issue. The airplane then performed as expected. Getting all ailerons in sync is easy with separate servos, with link rods the connections must be right on the TE of each aileron and not offset from the center.