Gosh, you have a Dash Hawk, so put the 20's in and monitor KR. Start with the stock heat range plugs. If you are unhappy with timing being pulled back to prevent knock, then go to the colder plugs and run the risk of possible fouling. This is basic. It's not hard. It's not rocket science.
Remember that you'll get the best performance from the hottest plug you can run without pulling timing. I'm running the colder plugs only because I've got a 3 inch catless dp, I'm not real time monitoring KR like you can, I have a very heavy right foot and don't drive in much stop and go traffic. I could probably do fine with stock heat range.