Good stuff. What Martzloff calls "Cascading protective devices" we called "layers of protection". Catch as much as you can at the Dmarks, bonded together, then polish off the rest before it gets to the equipment with point of use protection.
We also hung toroids on signal cables and power cables to damp out very short common mode transients.
We took several lightning calls a day down to one or two a summer in the 4 counties around Ft Myers with this strategy. We had over 1000 customers and maybe ten times that number of boxes.