A gag bit is not meant to be used on a horse that is still learning, that much I will say. I agree that you need to go back to basics to a degree. Before your horse can learn neck reining and being soft in a curb, he needs to understand a snaffle.
Its like me asking you to do calculus when you're still learning how to multiply and divide. You need to set your horse up to succeed and the best way to do that is to give him all the tools to succeed and make sure he is solid in the basics before you ask him to move onto something more complex.