I'm way out of practice plus I'll be shooting formats other than 4x5 but...
I built my kits with lens spacing from 1.33x to 1.5x. For me, I can't see the need for focal lengths closer than 1.33x but don't want them spaced too far apart either. I suspect if I was shooting a lot of architecture in tight spaces my lens needs would probably change.
FWIW, and for what I intend to shoot, and if I was shooting 4x5, my kit would consist of the following...
47 SA XL
72 SA XL
110 SS XL
150 Apo Symmar