I see that that collar is intended to be tightly fitted to the kettle and the corrugations help capture and transfer the heat to the kettle. I'm not sure you really need to do that. A wind-shield collar could provide much of what that collar does.
The purpose of a collar is to help channel the heat from the burner up the sides of the kettle. A piece of sheet metal wrapped around the burner stand that helps form a 'chimney' that contains and channels the heat, could be a less-expensive option.