>>300948961
With particularly good lenses, they might be good for +/- 3mm. Beyond that, you have a not-insignificant portion of the population experiencing mild to severe discomfort and eye fatigue. 

Two settings at 62mm and 68mm might do alright, covering 59-65mm and 65-71mm. The downside is that anyone at 65mm won't be having a great time.

>>300949135
Software adjustment does little to address the major problem of IPD mismatch, which is the optical strain. The software adjustment simply changes the scaling of the world to fit. If you've ever used the default passthrough on an Index, you know just how strange it is. The Oculus Quest passthrough has this problem too, though to a lesser extent.

>>300950018
There's zero chance Facebook is putting a motor of any kind into this headset.