your gonna add to many different dogs and have a hell of a time isolating traits and basically everything will be a scatterbred mess.. American Bulldogs by way of Johnson took to many years to get all quirks out because he crossed in ENglish Bulldog, which is a pug mix of the 17th century and not a bulldog) and he crossed in the Mastiff (which in origin was a 125lbs Pit bull like chain dog, thus BOUND dog Bandog/Bandogge..) If you put Bandog in the search box, you can find a good amount of info here on GPB.
There are already BLue Bandogs and they are Swinford Blues or Swinford Bandog... Infused and created by the Veterinarian Dr. Swinford who used Carver for his source of
APBT blood. THey tested his stock just like you would game dogs before 1976.
Chimera has Sentry Dogs which are Bandogs of this era bred at there finest.. They are
APBT by way of Sorrells and a smidge of Hammonds(perhaps) with Tosa.. He has very fine bandogs and the best your gonna get..
If you want to get into bandogs.. then sterilize your two dogs.. and start with bandogs.. You have no idea the genetic slop you will get when crossing those two.. I can tell you thats how those Hippo like XL bullies come about that and breeding with whopper dogs..
Whopper is a
APBT bloodline that is DDB influxed.. It was a import of now extinct blood for the DDB and the cross back into game dogs created awesome beasts and freaks of nature.. Most people dont know how to breed it or what they have so there is alot of whopper slop out there and a lot of OFRN dogs all slopped up with whopper traits. Whopper is a bandog as well and there are some fine whopper dogs in Oklahoma given you a 110-125lbs
APBT Hulklike bandog or bulldog.. Bulldog for game and quarry, Bandog for men and quarry..

I've bred whopper up to 125lbs and down to 35lbs all off the same stock.
Work defines these animals outside of DNA and well when we say DNA or Blood.. we mean the ENTIRE package, mental stability, agility, intelligence, heart lungs, etc... and you dont know any of this until you work your dog to its breaking point much like alaskan sled dogs...
You can breed your dogs if you want, its a free country.. just when the offspring turn out an bite someone be sure you say you have MUTTS and DO NOT even USE the TERM PIT BULL.. Be sure to say they are a mix breed or mutts because thats what they are. Without a pedigree of genuine origin with the dogs, your two dogs are simply just bulldogs themselves... NOthing less.. nothing more..
As a breeder if you can't keep them all, you shouldn't be breeding.. Because its a good chance you could end up keeping half and responsible for rehousing the others as they cause problems for their owners..