I cast my vote for 6/8" blade-width razors. Here's why: You didn't give me the option of any /16" blade widths. If you had done so...

  • 4/8" Just too small. I suppose a 4/8" wedge be just the thing for trimming a moustache or goatee, but certainly not for keeping my cheeks, jaw, or neck clean-shaven.
  • 9/16" I have five razors of this size: two AE Berg's, two Union spikes, and one "Case's Ace" (the first four are near-wedges/quarter-hollow, while the last is full-hollow ground). I often turn to either of the AE Berg (Eskilstuna) razors, and find that their very stiff grind more than compensates for their lighter weight -- provided that I don't go more than two days without shaving.
  • 5/8" I have thirteen razors of this size, of which five are near-wedges/quarter-hollow, and the other eight are full-hollow ground. I regularly use the stiffer grinds, but rarely pick up any of the others; my reluctance to use the hollow-ground razors is due wholly to a preoccupation with getting cut by them (this is totally absent with the stiffer grinds).
  • 11/16" I own eight razors in this size, and seven of them are among my finest shavers. Here, too, I prefer the stiffer grinds, and one of these can easily handle four days-worth of unshaven beard. This is my favorite size.
  • 6/8" I own six in this size, of which only one is a stiffer grind -- my Wheatly Bros. Wheat Sheaf. This is my favorite razor. The other five don't get used very much.
  • 13/16" Only one of these -- an F.W. Engels Leader -- and most definitely a full-hollow razor. In too many instances, it's an unwieldy size, which very quickly takes me back to that "getting cut" place. It rarely gets handled, and I haven't shaved with it in at least five years.

One other factor is the blade tip: I have come to learn that spike/square tips do not play nicely with a "meatier" neck, while round/French tips are quite accommodating.

Conclusions:
  1. Grind, size, and weight are a triangle, in which any two can generally compensate for the third.
  2. Beard prep, #-of-days-growth, and honing influence that compensation.
  3. Visceral feedback accentuates any fear of getting cut, increasing the likelihood that you will.
  4. For me, with minimal beard prep, mediocre honing skills, and a track-tested tendency to go 3-4 days between shaves, a 6/8" near-wedge/quarter-hollow ground, hunk of patinated Sheffield steel is the ticket.

Interesting. As I've written this, I've come to realize that those full-hollow, square/spike-tipped razors ought to be in the hands of others, who will use them...