I guess if we could go back in history it would help. Everyone has an agenda to their opinion. Bullmastiff is a comparitively new breed. Mastiffs and Bulldogs were taken there before Bullmastiff blood was added. Probably depends on the purpose the Boerboel was bred for. For leopard killing I think a smaller dog would be more useful. For pinning a lion if they are just used as holders then more size would be an advantage. So once again function is the criteria.

In Carl Semencic's book Gladiator dogs in the chapter on Boerboels there is one on p258. She stands 25 inches, weighs 112 pounds and looks like there is RR blood in her for sure.Even her colouring is similar.For contrast on the previous page there is a Boerboel standing 27 inches and weighing 172 pounds. This one shows the dark brindle from Mastiff or Bullmastiff.