I wonder if you considered moving away from knobs and buttons. It seems like you are designing a user interface for a piece of hardware instead of software.
For example, look at the similar FilterStation* by Audio Damage. You can adjust the Filter and Resonance together for either filter by dragging on the "1" or "2". Or you can adjust the Filter and Resonance for both filters simultaneously by dragging on the box that connects "1" and "2". You can also drag the numbers directly to make adjustments. I think the FilterStation GUI is quicker to work with because it is optimized for mouse control.

* Yes, I know FilterStation is simpler and the analog modeling is much cruder than The Drop.

