Something like this?
The only thing I can think of, and i'm not sure if it matters, but the where the blender circuit connects to the loop in and out jacks, the fx chain will also be wired to it. This shouldn't be a problem in blend mode because the switch will take care of that, but in fx chain mode, the blend circuit loop will still be wired to the jacks. Will this cause any leakage into the fx chain? Or is it pretty safe to say that nothing will be running through the blender at that point?