[DouglasCole]

One day I'll do what I keep wanting to do and tape down 1yd hexes on the floor during a martial arts practice and film the interaction from above. The studio we train in can do it, and we routinely use sword, knife, shortsword, one-handed axe, shield, spears of six to eight feet, and two-handed axes, which would get the reach thing.

Toss in a bit of unarmed striking and grappling, and I think it'd be illustrative.

For the point in "how many can be in a single hex," I'd guess that once you get more than one, things get decidedly cramped. Two is probably OK (and by normal GURPS rules, required for punching) if one assumes the target fades to the "rear" of their hex.

Try it: grab a yard or meter stick, and have two folks stand on each end. Even better, find a six-foot "bo" staff and look at where kick and punch distances are. Standing in a not-terribly-deep fighting stance for one person occupies most of the hex. Two can probably fit if they like each other a lot, or not at all. Three or more is "I can't move" territory and probably can't really be done standing up.