You can use more Cayenne is you wish. Red Pepper Flake is most commonly used for adding heat in North Carolina. Here is a North Carolina Style Rub I like...JJ
Carolina Q Dust
1/2C Sugar in the Raw (Turbinado)
2T Sweet Paprika (Hungarian)
1T Kosher Salt
1T Chili Powder
1T Granulated Garlic
1T Granulated Onion
1T Mustard Powder
1T Grnd. Black Pepper
1T Grnd. White Pepper
1tsp Cayenne Pepper, or more as desired.
1tsp Grd. Cumin
1tsp Dry Thyme, rubbed
Makes about 1 Cup. This has some Heat from the the jar but mellows when Smoked. If too Hot, reduce the Black, White and Cayenne Pepper.
Apply your desired amount of Dust to the meat, wrap in plastic and rest in the refrigerator over night.or longer. The day of the smoke, pull the meat out, add more Dust and go into your pre-heated Smoker...