The OD(outside diameter) is 3.875 inches, or 3 7/8 inches, so 4" at least. There would not be a lot of stability with that small of pot.
The Spirit Stove w/mini Trangia Windshield weighs: 6.4 oz / 181 g
The Spirit Stove from Trangia does have an insert to soak in fuel prior to lighting it. I would suggest using Denatured Alcohol or Solid Fuel Tablets to fuel the stove.
You can purchase Solid Fuel Tablets here:
http://www.campsaver.com/solid-fuel-12-pack