With a flat lens board, those min and max will relate more to a lenses FLANGE FOCAL LENGTH. Again this will just let you know if you can focus at infinity. If you want to focus on anything closer, you have to do the calculations or experiment.
120 is similar to 35mm lens, so you may like the 90 better. Since 4x5 is more square, you equivalent 'favorite focal lengths' may differ a little.
Realize, a wide, affordable ( read "slow") lens can be pretty dark on the corners when composing and focusing. This may take some of the fun out of getting good results when just starting out. Don't discount the 'normal' lens in this format. A 150mm with large image circle will let you practice the movements, has a bright view and can be pretty affordable. I shoot wide with 35mm, and MF, and thought 150mm would 'not be for me' in 4x5. However, after a few years of use, my 150mm is my favorite on the 4x5 camera (landsape).