I agree Macek does look like the sketch and should be checked out. Though, as you note, the MO is different and he seems to be too short.
The two pictures I posted on both sides of the sketch are of Ted Kaczynski, from the time period. It grew out of an investigation into Ted Kaczynski being the Zodiac.
IF Ted Kaczynski was the Zodiac, then he likely killed Cheri Jo Bates on 10/30/66, as she left the Riverside College Library. At Riverside they found a desk with a morbid poem written/etched onto a wood desk. It mentiones stabbing a girl in a red dress. Of course Aardsma was wearing a red dress, and there was also a morbid statement about death written/etched onto a wood chair arm. Both murders happened in or at college libraries, within a day of major Fall holidays (Halloween, Thanksgiving). Both victims were girls who lead clean lives with no clear suspects. Both were killed with approx 3 to 4 inch knife blades.
PA State Police were interested in the possible connection, and showed Ted's picture to a witness who said she saw a man with the exact same face at the PSU library the day before the murder, acting strangely and perhaps wearing an afro wig.