Im pretty sure that the application is about SMPS in middle or high power application.
Tipically in this case you have to know exactly the amount of DC current and AC current that tracks have to carries.
For example 5A for DC current + 1A for AC triangular current ripple at 500kHz, and dont forget that 500kHz is the main frequency of that current but there are also the armonics to take in account...
If this is you scenario the only way to make somenthing with sense is to calculate the width for the maximum DC current and then add some percentage of safety fot both, DC and AC current.
Remember that is more important to keep a safe "back way" for the AC current then skin effect especially in high power SMPS that tipically have frequency around 50kHz to 200kHz, depends on topology and application.
Only if you have very hard design with a lot of amps at MHz the skin effect becomes predominant, and the solution is not on PCB track width