First of all, on a '92 L27, the balancer uses (3) 6mm threaded holes to pull the balancer off. You can "force" 1/4-20 bolts in there but if you strip those out, your job of getting the HB off just got a little tougher.
The tool the manual talks about is a set-up tool for the crank sensor. With my 92, the crank sensor has adjustment "slop" and if you don't center it properly, you will wipe the sensor out, the engine will quit, and you will be stuck somewhere.
The set-up tool fits on the crankshaft where the HB would be. The tool has "slots" that line up with the crank sensor so you can tighten the hold down bolts with no issue of the HB tangs killing your new sensor. I hear that later model year Bonnies (series II) eliminated the adjust slots in the sensor and it is just a bolt-on replacement.