When I make hot sauce for my friend who loves heat, I purchase ground chili's from
https://www.spicesinc.com
Cayenne Pepper Hot Heat 80,000 - 90,000
Habanero Chile Powder 180,000 - 300,000
Aji Amarillo Chile Powder 30,000 - 50,000
This combination adds great flavor, and gives a burn to both the back and the front of the mouth. To me it is just important to have flavor as well as heat.