Brendan, I commend your effort and I wish you luck.
@TheRednose
I can certainly understand the assumed level of gameness in true apbts - and how that can solidify a level of reliability.
I also feel that larger pits - over 75/80lbs arnt necessairly game dogs. I work very closely with a Virgil mayday grunt dog who’s 75 conditioned. The rest that I’ve seen that large are scatterbred streetpits - not gamedogs.
You are correct APBT's that are on the huge side are not gamedogs nor would you want them to be anyway when talking catchdogs. You say you have some experience with Mayday, Virgil and grunts dogs, I have a lot of experience with game dogs as well. I owned dogs directly off mayday from victor, and many other dogs directly off great dogs and I think very few would have made catchdogs, not for lack of drive or gameness but for other reasons Im not going to go into. Just because a APBT is big does not mean it was not purpose bred, trust me when I say that. And just because an APBT is a few generations from the pit doesn't mean it isn't still the gamest breed outside actual gamedogs themselves.
When I made the Neo statement I did not realize you still wanted to do man work too. I personally think protection dog and catch dog work should stay separate. The last thing I need is any type of aggression towards anything but a pig when I am leading one in, or even more so when I am cutting one out. Imagine the train wrecks that could happen, though prob unlikely just imagine.
Everybody likes a jack of all trades but there really is something to specialization imo. I feel like this is one of those things, have a protection dog to protect you and a catch dog to catch and hold pigs. Now like stated before this is just my own opinion. If you simply want to make a better protection Mastiff or like you said recreate a coursing mastiff, I would guess large sight hounds like a hunting stag or other working large sight hounds and I would steer clear of any pure greyhound blood. And like you said APBT improves everything but I would keep my eye out for a line of larger working APBT's and stay away from actual gamedogs. That would be my thoughts on things.
Good luck in your endeavor and hopefully some of our rambling on here has given you some ideas.