Try one thing first. When it dies, chill the power transistor (black box on coil bracket) and the whole dizzy body. I'd use ice packs. This tests for a heat failed component. You should get a much quicker restart. Test one at a time. I'd also clean the dickens out of the connectors to the power trans. and dizzy, as you could be getting a heat expansion disconnect in the connector as an iffy connector becomes non connect with a tad of heat induced physical connector creep. And "resistance tends to increase with the temperature of the conductor"...

Not responsible for advice not taken...