Yeah, don't worry about the fix just yet. It is there to prevent errant trigger pulses causing extra shots. You aren't having that problem. As mentioned, put the dwell up to 30 to ensure the solenoid gets enough time to pull in for all instances.
Don't use the single oring on-off top configuration. That is only for older valves that are designed with the machined recess in the on-off area. All newer valves don't have that recess. If your valve uses two orings for the on-off top, then you can't use just one.
The 0.725" on-off pin was for use with the urethane inner oring. When AGD started using the quad oring, the sealing surface was lower so a shorter 0.712" pin was needed to maintain the same pull distance for timing purposes.
Your plunger measurements look good. Always use the emag specs when using any valve in an emag. Make sure all your electrical connections are good. If the battery is good and the valve is functional, then it should fire in electronic mode if the trigger input is getting a low pulse.
You can verify the trigger operation with the valve out of the gun. Hold down the back of the sear so that the sear is in the reset position. Then gently pull the trigger until the solenoid activates. You can see where the trigger causes the activation. There should be a bit of trigger movement past the point of activation before it hits the trigger stop. There should also be a bit of trigger movement past the reset point going forward as well. If the trigger is too tight, the magnetic hysteresis of the HES won't allow it to reset after it enters the magnetic field. It won't be able to get far enough away from the magnetic field to reset.
Except for the Automag in front, its usually the man behind the equipment that counts.