What even is the point of separating blue/red? Instead use reverse kinematic to put raise/lower bucket on one and tilt bucket on the other.
Then another virutal axis to do the "digging arc of circle" in a single action.
There's a ton of reasons that an operator would not want to rely on reverse kinematics. They are a professional who needs to make sure they don't slam a big machine arm into something. While reverse kinematic control is nice as a user, it has multiple possible solutions, some of which may not be acceptable.
My guess is grading. When you're grading you need to supply a different amount of power to the arms depending on the angle. But I'm no expert in this. Seems to be the standard euro configuration and I was looking for this to setup a simulator