Hi Grumpy_Mike!
Thank you for your insights, I really appreciate them. So it seems that using a Triac-based, zero-crossing power tail may work very well in terms of keeping humans isolated insulated from mains voltages while also affording us the ability to measure impacts on the basis of 1/2 wave (i.e. 8.3ms) increments. I imagine that the sags experienced by the equipment must be longer than 3 cycles to cause the reported problems. I'll circle back when I have more data. Thank you again.