WMS = Wheel Mount Surface

Someone will have to measure it for you, if you do not have an A-D 3100 to measure. The following measures might be what you are looking for?

Here are measurements of center-to-center of wheel-to-wheel (center of tread tire-to-tire)
front = 56.75"
rear = 61"

(also shown here)

Note: front measurements are slightly different in 1949 (huck brake spindles?) and in 1954/55