Quote Originally Posted by Konical
Good Afternoon, Matt,
This is, if I understand correctly, essentially the same idea as Donald and Lee L have described; it just uses enlarger head height instead of print length as the measurement. Since my Beseler MCR-X has a scale on the right-hand standard, it's the most convenient way for me.

That's it exactly. The change in height of the enlarger is directly proportional to the change in width of the print, so percentage change in enlarger height (new height/old height) would result in the same number as LN/LO, so you square that and multiply the original exposure time by that number.