I thought I'd mention this old trick I've used over the years.
Secure a piece of 1/8" or 1/4" copper bar about 1" wide and 5" to 7" long.
Drill two holes near the ends.
Drill & tap two holes for 13mm spark plug threads at the approximate conductor distance of your feeders. Insert two non-resistor plugs of your brand choice.
I use Champions.
Put it adjacent to your incoming feeders by means of two standoff insulators in those end holes. Mount the assembly with the plug tips facing towards you, or use some 90 degree stock to point the plugs upright so you can see the gaps working.
Run a good-sized wire from your station ground to the copper bar.
Tie each feeder lead in turn to one of the plug tips via short jumpers.
Adjust gap according to modulation and power levels used.
You now have pretty good surge protection from something that was designed to take a lot of sparks in stride!
73DG