They call it off-set, I call it 'retardation'.
Looking at the chainset from the off-side (transmission side) of the bike; when the major axis of an ellipsoid is vertical, the crank should be at aproximately 2:30, or 15 degrees above horizontal.
This angle varies a little bit for a 'normal' bike layout.
A lot of people believe that the crank should be horizontal, or at about 4:30, about 30 degrees advanced.
Research suggests that 15 degrees retard is optimal, and I agree.
I cannot see that reducing that angle of retardation, or advancing the orientation would provide any advantage whatsoever.
However, the optimum retardation angle will be different for recumbents, and different again for different recumbent layouts.
If 'out of round' chainsets become popular again, will the correct orientation be adopted?
At least, this time around, we have internet forums, so some people will know their onions.