So I got a new Surface Dial and did some experiments this evening. Combined with the pen its really cool!
Check out this video to see how usable it is with SONAR. I have a Surface Pro 4 which doesn’t support the surface on screen placement, but besides that it works fine. In the test I’m just binding keyboard shortcuts to the Dial. SONAR doesn’t yet natively support the Dial but based on this I’m definitely considering implementing this.