B&W TV Focusing

[VintagePC]

I was playing around with the focus magnet on my Fleetwood today and after experimenting for a bit, I was wondering what the common practice is for best picture adjustment.

Essentially you can reach three states - underfocused, overfocused, and exactly focused.

I find that while it's easy to focus exactly (my set, anyway) and get incredibly sharp lines, in practice this produces a rather difficult picture to watch because of the sheer amount of "dark" space between the raster lines. Thus, it's easier on the eyes to slightly de-focus the electron beam so the lines blend together a little better. Therewith, you can overfocus where you have the beam "cross" itself before hitting the screen, or you can "underfocus" and have the focal plane be in front of the actual phosphor screen.

What do the folks here do or prefer for their sets? Feel free to turn this into a discussion on the finer aspects of focusing a B&W, this isn't a particular answer I'm looking for but rather the theory/comments and best practices surrounding the setup of a tube-based tv.