Personal Pref: All the way forward lets you run the chain the longest without re-cutting. Further back makes the bike ride better (longer wheelbase) but you may have to cut the chain once again before it is wornout.
IMO
So your saying keep the same chain no matter how much it stretches as long as it still fits on the sprockets?
Well, sort of. It is self limiting. At a certain amount of stretch, it won't fit the sprockets, and that's our clue to change it.
In fact, if you set the wheel/cut the chain so that the wheel is 2/3 of the way back, by the time it reaches all the way back, it probably won't fit the sprockets anymore. But assuming you're willing to trash the sprockets or were otherwise planning on replacing them, you could cut the chain and use it some more.
IF you started full forward, by the time its 2/3 of the way back it is probably time to replace it.
I just know on the CB750 you can tell the difference in ride quality when the wheel is 2/3 of the way back v all the way forward.
