How interesting this is. I'm putting a 47mm S-A XL on my 4x5. The lens is replacing a lesser 47mm S-A f5.6 (pic).
My helical has distance markings but I'm almost certain they are arbitrary.

I plan on first getting the lens board just right so that when the helical is fully retracted it is on infinity. Initial infinity spacing will use brass shims and gaskets. Then I will focus using on the ground glass at my favorite distances, 3', 12', 24', mark them and be happy.