OP, sorry.....anyone can say they are a trainer, and I've seen more terrible trainers/handlers than I have seen good ones in the short amount of time I've been heavily involved in the sport world (especially on the pet trainer side of things)....so it really means zip to me when someone says they are a trainer. Like that's some golden ticket that means no one should question their methods or theories.
ETA: Here's Lou Castle's website. Maybe it'll help you out a little.
"An excess of size is an unserviceable feature for breeding, his powers of endurance, his speed and the smartness of his movements suffer in all circumstances. Giants are never nimble."-Creator of GSD