Keyforms lag and crash

Cartoonscott

Here is how my arm is set up

Rotation deformer on whole arm
Inside that is Rotation deformer on forearm
Inside forearm is approx 10 hands with deformers on them to turn those hands on and off

When I try adding keyforms to the arm and forearm I get a message sayign I am assigning too many parameters to the object. Then it either takes a long time for the keyforms to add or the whole thing crashes/freezes

The set up of the arm seems pretty standard for a arm rig but Im obviously doing something wrong. What is the solution please? Thank you