Autosport Labs

I was going to use it on a 78 280z tach, but I just upgraded to a autometer. according to schematics I've seen, in order to use the tach on a wasted spark system, you have to combine the three spark signals into one with diodes. I thought this would be the solution im looking for since it looks like...

Maybe the image will help, again, 6cyl wasted spark, would I use a signal from Spark a for coil 1, spark b for coil 2 and spark c for coil 3 and leave coil 4 alone? Any help would be great.

Im in the process of getting the tach working on my 6cyl wasted COP system. Am I supposed to put a signal from each spark outputs to the adaptor?

I.E. Coil1 = spark A, Coil 2= Spark B, and Coil 3 is spark C?

Can someone verify.