You could try to use a more recent version of the stock Apple control panel for date and time (like from Mac OS 7.6 or probably 8.1). It resembles several of the SuperClock features and should run with System 7.1 as well. The font should appear accurately aligned in the menu bar.

Instead of the 12 point Chicago I prefer a 9 point Helvetica for the clock, however (PowerBook user). With a screen 640 pixel wide this setting saves some space for other menus. You probably might even consider to memorize the day of the week ;-)

Cheers