By using the term natural horsemanship, trainers are doing things that often replicate what happens in the wild herd. When training isn't fear based there is less chance the horse will let your down in a ticklish situation. I've seen horses forced in their training and the moment stress got to be too much the horses blew up. 30 days isn't really enough time to build a solid horse that you will feel safe with. Half a dozen rides doesn't cut it. Try to find a trainer near enough that you can drop in a few times a week. Also, be sure to take a few lessons on your horse to get a feel for it's training.