You wrote:
Not sure lightning will be stopped by a 6mm gap in a breaker.
Lets discuss. The breakdown voltage of air is about 30 kV / centimeter. A 6mm gap would take 18 kV.
Here’s where it gets interesting. The normal breakdown voltage for insulated 14 gauge wire is between 600V and 1,000V. Plenty for a home, and totally inadequate for lightning. Any surge higher than that will burn through the insulation and short to ground.
The normal surge testing is at 5kV, which is believed to be the maximum voltage a home could receive from the electric grid. The reasoning is that the natural inductance, and low insulation strength (relatively) of the wiring that goes to your home would mean anything more than that would naturally find some other path to ground.
So, for anything that comes in from the mains, 5 kV is the absolute worst case scenario. What about a direct strike? If you have 18kV at your breaker or even power switch you have a hole in your living room. :)
Here's where I'm at. In the half dozen or so cases where I've lost equipment or been present when equipment was damaged it was not from a direct strike like that.
So, yes, pulling your gear is the best way, but 99.9% of your damaging surges won't be that kind of strike.