We have a pitbull mix i got as an 8-week-old pup.
I never let him outside of the fenced back yard unless i was there. For the 1st 9 months or so, he would run out to "meet" other dogs walking by and I would immediately intervene (sprinting to engage). He didn't want to "fight", just do the normal butt-smelling stuff.
Understandably, the passersby did not know that hence my instant running out to secure him and apologizing profusely (then instilling hefty negative reinforcement).
However, after nine-ten months of getting his head literally hammered (not literally by a hammer...just my hand), he learned unconditionally I was the alpha. We also were lavish in loving on him - he thinks he's a lap dog..... at 85lbs, he's a bit much!
I had consulted a police K9 trainer i personally know about socializing and training strong-willed dogs. As I had participated in some of their "training events" (I was a bad-guy wearing a padded suit!) multiple times I had seen my friend use some seemingly too-rough discipline on his 105lb Belgian Shepherd (a sharp crack on the head via his 6 D-cell MagLite). He assured me then the dog was OK and some needed a little more "convincing" than others. He just seemed strange, but he had been a K9 trainer for over 20 years and was well-regarded in police K9 circles (he was a well-known trainer in the state i lived at the time).
He encouraged me to have my young children involved in the leash training i had learned from him as well. It was simply making the dog sit if he pulled the leash at all. With the added pronged pinch collar to assert the dog's low position on the authority "totem-pole" our dog learned very quickly who was who in the "pack" pecking order.
It has all worked very well and our "dangerous" pitbull is very well adjusted (we semi-frequently have 25-35 people at our house for my wife's work functions). He is very social and loves being petted (and fed!).
When i am working outside on our never-ending landscaping projects/updates, he will just lay on the and driveway in the sun. If another dog walks by on the sidewalk, he remains sitting and doesn't even stand up.
But all this positive behavior came after a year of (seemingly harsh) head-cracking negative reinforcement of unapproved behaviors.
He is a superb watch dog though. Our neighbors (we share a fence with) have came up the stairs to our front door (when we weren't home) and reported he was nothing but 85lbs of popping teeth and growling/barking.
It took nearly two years for our dog to accept our friends who come to take care of our chickens (and have known him since our adoption) when we weren't home. Now, they board him at their house (they have 3 very small kids) and he protects their house and kids the same as at ours and recognizes them as Alpha's as well.
It all takes a lot of time investment, but is well worth it.
Incidentally, my wife is his "favorite" and he is usually not more than a few steps from her. However, he often shadows me (like now as he lays at the other end of the couch). In fact, if i lay on the floor he will be instantly come over to me and try to lick me to death.
He knows he is loved, but had to learn the "hard" way.
It was suggested you are playing with fire. I'm not sure if you agree with that, but if not, why did you take all of these elaborate precautions in handling the pit?
These "precautions" are reasonable and prudent steps to take with just about any large strong breed or mix. I had a lab/rot/border collie/golden retriever mix, his dad was 130lb so I knew he would be large and strong ( he ran between 90-100lbs when grown) . I did everything I could while he was young (starting at about the 6 or 8 week mark.) I just about "put the fear of god" in him and as far as he was concerned I was god. He was one of the smartest and most obedient dogs I've ever had or known. Yet I did not leave him around people he didn't know and had to warn people to not go in the backyard without me or someone he knew was in charge. A repairman made the mistake of thinking he could just go get a tool or something he left without having my roommate go with him. Guess what, he got bit. Nice guy though, he had a sense of personal responsibility and said it was his fault.
Any Every dog, (even small ones, just because) should be trained to have manners and obedience. I abhor untrained dogs and believe their owners should be sent to "retraining" or maybe Shock Therapy. Nothing worse than an untrained dog, barky, or even aggressive, no matter the size. Well, maybe untrained children are worse than an untrained dog.
Sorry thing is it's not even that difficult, just takes time and a little dedication.
That said, I volunteered at a "Bully" rescue in Fresno while there a couple of winters. We had dogs that only certain people could feed or clean the cage. There were certain dogs I would avoid but the majority were just dogs.
We own whippets now and I wouldn't trust them unsupervised around kids they didn't know.
To the OP, good luck with the new dog, keep your eyes open and be ready.
Geno
PS, isn't it a wonder what poor backyard breeding can to a dog line. There's so much aggressiveness bred into so many of the pit lines it would take a few decades to breed them all back to "nice".
