I ran Bosch platinums in my Chevy 5.7 liter pickup for years. Never a problem. Easy starts, excellent mileage. These were the satndard plugs, not those multiple electrode things they sell. Bosch has, I understand, one of the lowest firing voltages of any plug.
We don't use Bosch anymore, unless they are vehicle specific stock plugs.
BTW,platinum tips have absolutely nothing to do with the heat range.
Use the factory heat range plugs. Your objective and goal is that they stay clean under all conditions.
If you are racing or highway driving exclusively, you can go one heat range colder.