I commonly print images up to 40 inches using a Besseler 23 IIIC condenser and Rodagon 80mm off b+w 120 25 iso films. The distance form lens to floor easel is 76 inches. The acutance is good, but at these enlargements should I get a different lens? 4x5 format would help, but for mobility I must shoot 120. Also, am I correct in assuming an aperture of f11 will produce the sharpest image? Film flatness in not an issue as I use a double glass carrier.