Yeah I kind of gathered tosas aren't necessarily the kind of dog to be feverishly dragging on the lead after every little cocker spaniel they see.
I would be in trouble if any one of them decided to drag me, as they can easily do so :( For me, it's more mental control over them than physical. When walking on city streets, i do give other dogs a wide berth, preferably 10-20ft or so. And i carry pepper spray just in case my dogs get out of control and lock on to another dog. I walk them with regular flat collars and 6' leashes, but if i need more control of them (like going to Petsmart), gentle leaders work fine.
Tosas can get that way, just like any dog, if someone doesn't know how to control them....