I spoke with Mica regading this via email. She says I'll have to replace the Volume and Pan controls to work with an additional Filter. I'll also have to have the original filter modified.
Anyone have any thoughts on having 2 volumes and 2 filters instead of 1 volume and 1 blend like in the signature set up?
I've attached my thought on the layout which should fit the control cavity.
I have to say I was very impressed with the labor rate to modify my bass, and have it revisit the factory for a fresh setup.