Most typical aspect on porthole sets?

[cuteorkill]

I have yet to acquire a porthole set but have noticed the image being displayed a few different ways. Despite the source video of 4:3, the image is often seen distorted to fill the screen. Was there a usual default that the manufacturers set (see graphic)? Were controls for the vertical and horizontal size of the image typical for these sets?

I'm not too sure I'd want to distort or overscan too much. Choice D seems a decent compromise, but what are the rest of you doing?