In order not to upset the hard-core amateur astrophysicist lurking just under my skin, I have to look at the star maps in Stars Without Number as, um, hyperspace maps - maps that are only relevant to the extra-dimensional space that starships hurtle though. This space bears no relevance to real 3d space - just enough pseudo-logic so that the sleeping astrophysicist will not awaken and rain on my parade.
But . . . let's assume that the maps bear 'some' relation to real space. Kevin Crawford says very little about the 'shape' of human-space, or its dimensions. The most explicit snippet is this:
"By 2600, the frontier of human space extended almost ten years of spike drive travel away from Terra. Even after taking Jump Gates as far as possible, a fast pretech courier ship required a year to reach the farthest colonial worlds."
That date is just before the end of the Golden Age and the beginning of the Scream, so those dimensions should pretty much be the height of human colonization in the galaxy. Ship technology was also at it's height, so spacecraft could jump one hex per day. Ten years equals roughly 3650 hexes. The author very carefully never states the size of hexes on the star maps, so if we interject Traveller sizing - which if memory serves correctly is one parsec, we get:
3650 hexes X 3.26 light years = 11,899 ly
So, human space has roughly a 12Kly radius. A little image stealing and circle drawing gets us this galactic map:
That's a fair chunk of the galaxy colonized, but it still leaves ample room for who knows what. Now, I can start thinking about SWN's 'Known Space' visually - inside my noggin. Not that I really need to, but it's more comfortable that way for me.
So, that ends my thought experiment for today. :)