Cool, I'm glad you found them useful. Hopefully there are not too many holes/misinformation in them... I'm new to this as well.

If you have low Z injectors, from what I understand, when you set up the software peak and hold for MS2, you can get away with like 90 or 100% hold times as long as the engine is at idle or low load. Don't load the motor up like that though. Since the load is low, the fuel pwm duty will be low, so they will have time to cool down between squirts and not overheat. If you run them 100% current limiting (no current limiting), they should stay open while you tune in the idle.

Once you have it at a steady idle, you can start decrementing the 'hold' number of the peak and hold settings. Decrement by about 5%, burning the ecu each time, and give it a moment to settle out. If the idle is still good, continue to decrment until you find the percentage that the idle degrades. Then, go up like 3% from there and you've tuned in the peak and hold for your particular injector characteristics.

My hold percentage came out to like 75%, which is higher than I expected, but I'm not sure I'm entirely done with that setting since my idle was not completely stabilized.

Check out: Youtube: "Evan's Megasquirt Build Ep 25 - High vs Low Z Injector Sizing / Driving / PWM Basics" if you have 20 minutes to kill and don't have a full understanding of low Z peak and hold.