LT3092 and large guard rings
The idea with guard rings is to prevent leakage current. FR4 has a volume resistivity (varies from manufacturer) as low as 10^14Ω cm. What you have is most likely sufficient for the leakage current you may have, but since it's easier to run traces than to calculate the leakage, I'd add another one around the pins of the dip switch.

Make sure you pull the ground plane underneath the fence and add a guard trace underneath also in the layer below the top layer. (while maintaining a proper ground to the LT3092)




  Minimize board leakage by encircling the SET pin and circuitry with a
  guard ring operated at a potential close to itself; tie the guard ring
  to the OUT pin.


This is what I would do (because the pin 6 is an NC pin and not a DNC pin):