I am going off track but I think the reason that you are looking for test equipment is just as interesting as a discussion about it.
Have to ask. You did disconnect your antenna before the storm.
The other day had the antennas off before a storm rolled in The leads were sitting on a grounded plate. Later could hear a ticking so I went in the shack and the antenna lead was sending half inch long sparks to ground.
The sparks were not from lightning per say but voltages were well above what I would expect most hf receivers would handle. They were not the million ampere discharge.
I don't believe that any "lightning arrestor" is worth much. Just a step above deer whistles.
Lightning is going to do what it is going to do.