Oh you can have some in the rub but definitely no need to do a high content. There's natural sugars in the meat that will caramelize. I used to wonder and worry about what rub to use but now it's more of a simple SPOG (salt, pepper, onion, garlic)So no sugar in the rub?
I cook mine @ 300* no foil and shoot for around 45 minutes per lb...so you're definitely not cooking too hot.What temp did you cook those butts? Could mine be too hot?