MSD ignition tach output question

[PBucch]

Hey guys, I searched and checked out the JWT page, but am still a little confused I am almost ready to start my car, got a few things left. Im putting a KADE into an 89 chassis, previous owner had an MSD booster and coil installed and the stock p00p was nowhere to be found. I know the OE stuff is great, but I dont have it.

Going by what he had hooked up I can tell what powers the coil, I dont have it in front of me sorry, but which wire of the three that goes to the coil is the tach signal?

THe booster puts out a tach signal at "12v square wave signal, 20% duty cycle"
Will this be fine for my DOHC tach to read? When the single cam was in hte car it had no tach reading at all, i assume it just wasnt hooked up....

Im thinking if it reads fine I can just put a plug on the wire and plug it into the boosters tach signal output right?

Thanks for any help,
Paul