It's good to have a tapered surface back to well defined TE. The taper reduces the weight of the surface as a major benefit. The narrowing reduces the width of the TE. Thick trailing edges of any shape are less than optimum for drag. The TE width doesn't have to be sharp but benefits drag and flutter resistance when narrow. What you do need is a well defined one, and having a bit of thickness helps create and maintain the definition. Having a narrow, well defined, uniform TE helps reduce flutter tendencies. Flutter is after all a fluctuation. And having a somewhat narrow place for the upper and lower air to meet that isn't sloppy round or vaguely round removes the room for fluctuations to develop.

So the best would be a taper to something like 1/16" thickness. The taper will then remove an appreciable percentage of wood. Lighter surfaces are less apt to flutter. And the edge will be small enough to not create a big bluff ending so won't cause excess drag. Or give flutter any room to build. But the edge will be thick enough to resist hangar rash.

As for any aerodynamic magic, don't look for tricks. The urban legend stuff comes out in the explanations for all the other shapes.