Maybe I'm missing it. But where is the single wire specifically only for speed pulses from the ecu to instrument cluster ?

Or is the drawing weird because it's trying to show 3 different engine setups on a single page ?

If there is a single wire from the ecu, then it will either be a pulsed 0/5/0/5v etc etc, or a PWM signal

A multimeter may give an indication of this if you're lucky. It would certainly be able to give you a dwell or duty cycle reading if it's a PWM signal. And if it's a 0/5/0/5 etc when moving slowly a voltmeter should offer you some into.

You really need a scope though. And again if the drawing looks right, your VSS is already a 3 wire hall effect which will give a digital output and most likely 0/5/0/5 etc