i have a real good friend who used to participate in live pigeon shooting a lot, his advice on colobaire shooting is not to do it, throwers are to easily bought off. he recommends staying with box birds, the play is much fairer. he and his son are two of the best box bird shots in the world, at least according to what i can find out.
my wife used to referee, score , and chase cripples when she was in high school, at a very large gun club here in texas which still hosts both kinds of shoots, shooters come from all over the world; it's not dead, it's underground.
mr. p. thinks zz birds are good practice , as are skeet and trap. some people say skeet is of no benefit, but in box birds a real smooth swing helps a whole lot, it doesn't hurt in any game.
his credentials are hard to give here without getting some animal rights activist on his case, but i'll give you a hint, in box birds you are handicapped by how much money you've won, mr. p. has the longest established handicap ever given, with 0 chance of moving forward, and no company even near joining him.