John Mack's Cluster Igniter Tip

At the Tampa TTRA launch, I asked John Mack what the small drawn dots meant on the Estes igniter paper tabs.
He explained those were tested and matched igniters.

When John pics igniters for use in clusters, they are tested using a small multimeter.
All three of these igniters had 0.8 ohms resistance.
Matched igniters are more likely to give simultaneous ignition on all three of these parallel clustered engines.
From left to right, a B6-4, C6-0, B6-4.
In the stretch Super Alpha engine mount is a C6-5.

I know - the epoxy glued CHAD booster engines don't follow the NAR safety Code guidelines.
But it sure looked cool going up!
That had to be one of the higher booster separations I've ever seen!