What kind of blacktail info are you wanting? And you're talking blacktail rattlesnake (C. molossus) and not AZ Blacks, right? I've never had issues with blacktails being mean or aggressive in AZ. In fact, most of the specimens I've encountered barely rattled to let us know they were there and they were very docile when handled. I actually used to grab them by the tail and pick them up. I have a picture of that somewhere, too, from down in the Chiricahaus. The blacktails in west Texas were a whole other ballgame, though. They were aggressive AF and would strike like crazy.
We had a a set of young Mohaves from west Texas with the neurotoxin. They were born in captivity to a 4-foot female that was captured near Hueco Tanks. It was fun to watch feeding time. It gave you a good perspective as to how lethal the Mojave toxin is. They would strike the mice we fed them, the mice would jump straight up, and hit the bottom of the tank dead with minimal twitching, if any. One of those beauties escaped on me during feeding time once. It hit the ground at my feet and went under some tanks/tubs on the floor. I had to go and lock myself in a 7x15 room with it and start moving tanks, tubs, and cans around to get it back in its cage. That was kind of unnerving.