How can I adapt the spacing between track and signal polygon?
Hasn't the polygon got an individual aura? No, the spacing is defined by the spacing of the two involved signals. The track's signal as well as the polygon's signal have a minimum spacing.
(Image 1: Enlarge the GND signal's minimum track spacing to 0,6) The following image results:
(Image 2: All distances to signals other than GND enlarged)
Instead of adapting the minimum spacing of the GND signal you might consider to adapt the spacing of a particular signal or signal segment other than GND.
(Image 1: Enlarge the GND signal's minimum track spacing to 0,6)
(Image 2: All distances to signals other than GND enlarged)
(Image 3: Only one signal with a plus of spacing)