Second, I make sure I use the right sized plastic plug. It's not intuitive, because the nozzle throat size is completely unrelated to the motor size.
This is indeed important. And for newbies, one also has to make sure that the little bit that connects the plugs together in the molding is also removed, so that the blunt end of the plug is actually what is pressed into the motor. If the connecting bit is left on the plug won't go in far enough and if you try to force it, that will break the igniter's bridge wire. Otherwise it is really uncommon in my experience to have the bridge wire broken using the correct plug.
I just cut the plug color listing out of the Estes motor instructions (there's a set in EVERY package) and tape that to my plug container or other convenient place. But having the actual colors on the cheat sheet is useful. I have a big one that was posted here some time ago that I put on the table with the flight cards at every launch I run.
interesting that you have B8s on your sheet. They have been gone a loooonnnng time. Also, E12s no longer use the yellow plug. They come with black plugs now...and that's what current instructions call out.
Also, the little orange plugs are also used in 1/4A3 and 1/2A3 motors, and the yellow plug is also used in 1/2A6 motors (18mm 1/2As).
For all, here's a quick shot of current motor instructions. This comes in every
pack of motors. It covers much of what has been discussed in this thread (except ProCast and other "enhancements").
I will add that ProCast has made my Solar Starters (the straw/yellow colored ones) essentially 100% reliable. But as I noted previously, I didn't have a big failure rate before.