My thing is...
You want to own and work these kinda dogs...cool.
I'm not one for bsl of any sort. But you better be doggone well prepared to own a high drive pitbull cross mastiff with a nasty disposition as well it should be as per the breed focus. Anything less is a watered down version and thro back dogs come along with every litter.
But to sell them to regular folks as the ultimate family guardian is irresponsible IMO. These are not now or ever were bred to be owned buy regular families in a normal household situation.
Own,work, and breed them as you like, i like em and think they sre pretty cool. But sell them in the form they were intended? Nah...
ESP not to novices or for run of the mill home protection unless you want to add fuel to the anti's and hand PETA a present gift wrapped.
https://m.youtube.com/watch?v=bibWfupJEog