I think Rollie's Dad's method is rather ingenious. The primary purpose
is to remove the twist from the bed. It won't ensure the lathe is level
from end-to-end or side-to-side. The purpose of leveling the lathe
isn't to have it level, it's to remove the twist in the bed so that the
the orientation of the headstock/tailstock/carriage are the same as the
tailstock/carriage travel up and down the ways. The machining operation
could care less if one side/end of the lathe is higher than the other.

I've done it both ways and Rollie's Dad's method produces perfectly
adequate results. It will also detect whether the headstock is
pointing up/down relative to the bed. Much more difficult to fix,
though. And not guaranteed from the factory. Best of luck.