You can shift this thread yourself.
Bottom left of the page is Shift Topic, click there and just follow your nose.
For SMPS it'll be working in the 20-60 KHz region and probably the best way to use it is to work backwards from the PCB in which it was in. Hunt out the datasheet for the controller and you just might see a 'Typical application' that matches your PCB layout. If you're super lucky the schematic might even list suitable cores and wire gauges used.
Some little detective work can teach you lots.