Don't get hung up in the breed terminology, especially since Bombay is a special combination that produces many kittens without the perfect Bombay definition. You cat like ours has terrific traits of Burmese cats (Bombay cats are considered black Burmese cats by many experts !!) as well as some of American black shorthairs. You should consider these great cross-breed traits as special to your cat and enjoy him. 11 to 12 pounds is normal adult male weight in these cases. They are terribly intelligent and pensive about everything. Definitely trainable by someone knowlegeable like yourself. You are very lucky to have him as a member of the family !! Ours is 2 years and 8 months at this point and is firmly entrenched now. Really makes life interesting and fun.This entire discussion on Bombay Cats intrigues me. We have a cat that was dropped off and abandoned in late February 2017. He is not a Bombay, as he is a black and white Tuxedo cat. Other than that, he has ALL of the personality traits of a Bombay including silky fur for his black portions of his coat. He is also a solid robust cat, much heavier than he appears. Our older male DSH tabby is a long and lean cat at 8 to 9 pounds, but Purrcy is edging in on 11 pounds, even though visually he is much smaller than our older cat! Our Vet estimated that he was 1 to 2 years old when he was dropped off and he adopted us! He showed up at the backsliding door to our deck and was very comfortable and ready to walk right into our house. We only let him in and kept him in a crate when it dropped to single digits outside, until he was cleared medically to be around our other cats. all of the walking around my feet and playfulness applies, he is VERY intelligent and trainable. Of course my other cat at over 11 years old I also trained, and as Purrcy is learning to do, responds to voice commands.