I took a smoking class and believe it or not, the teacher didn't use anything but charcoal and it was delicious. We even had 2 of the bbq judges in the class and they couldn't believe it either.
I made some really good chicken the other day on my grill. 2 chunks of soaked hickory on top of charcoal. To make it last longer, put in unlit coals first, with lit coals on top. The bottom layer will eventually light and continue the cooking.
Unfortunately, I live in Missouri and King Taco is only in California. Have you thought about using Sour orange juice? I think you could substitute 1/2 orange and 1/2 lime juices to make it sour enough.
I sure wish I could taste that sauce. Once I had some taco sauce at a local place and it was so cinnamony, I never went back.
I make my sauce like this, and I love it...
Put the stemmed chiles in the water along with the onion and garlic cloves. Bring to boil, reduce heat and simmer 10 minutes or so to soften chiles.
Put this all back into a skillet and "fry" it in the corn oil to get rid of the raw tomato taste. Cook for about 10 minutes and, if you want to, strain. I never get rid of the seeds because I like it hot, but if you like it without so much "fiber" or heat, you can get rid of them.
I like it just like this, but if you want it strained, that's okay with me.
Tomato paste is too sweet for me so I never use that, but if you like a thicker sauce you can use tomato sauce instead of the tomatoes.
You can control the heat by adding more or less tomatoes.