You don't need paper to compare. Take a picture of a newspaper, full frame, middle aperture(where
most lenses do best). Raise the enlarger to the biggest print you wish to make. Enlarging lens set to
5.6(the largest aperture common to both lenses), and examine center, edges,corners,etc. with a
grain focuser(keep turning it to face the image center. Then compare at a smaller aperture.
Use what you like, if it's the 4.5, keep the 3.5 for hard to focus dense negs.
Good luck