Frank,
The view camera magazine article indicates two 75 mm Caltar lenses. The earlier a Komura manufacture and the latter Rodenstock. The earlier lens had an image circle of 170 mm and the latter an image circle of 195 mm. Both were mounted in Copal O shutters.

The fact that you indicate softness in the corners leads me to believe that you were exceeding the coverage of the lens. The diagonal of the 4X5 format is approximately 6.4 inches (sq root of "a" squared plus "b" squared) that converts to 162.56 mm. Thus a lens would need to have an image at least that large to cover the format. When you indicate that you used slight tilt (wouldn't make any difference if front or rear) you are increasing the effects on the size of the diagonal of the format. Tilt is the greatest user of a lenses covering ability.

Most usually the coverage ability of a lens is not a sharp demarcation point. Rather it has an increasing degradation effect until the image circle is bypassed. The reason for this is the penumbra effect that you have noticed when you dodge a print. As the dodging tool is raised from the paper the shadow edges become less distinct. This softness that you noticed would become more noticeable the larger the degree of enlargement of your print.