I am curious how one would use an ON-OFF-(ON) switch as an ignition switch, unless it had two poles. Still, if (ON) is to start, then the engine will stop on its way to ON.
The breakers look like Airpax, which are very good. You might check around for better prices.
1975 32' Flybridge Sedan, twin Perkins 6-354 diesels, 1:1.53 velvetdrives, 16 X 19 props. Merritt Island, Florida