No offense taken to the beginner comments, I fully realize that I do not know what I'm doing! That's why I'm here asking questions and reading and learning the best I can. I want to do right by him and I definitely do not want to hurt him. :) He tossed his head as soon as he saw the bit, and I've only ridden him twice for a grand total of about fifteen minutes (once in his halter, once in the Dr. Cook's bridle) so I really do think he's had some bad experiences or perhaps has some residual dental issues. If nothing improves I will be giving the vet a call again.
With regard to the bit size, I was shocked! He looks like a normal horse to me, he measures at 16 hands and while he's big... he just doesn't look THAT big. It's mainly just his face LOL. He's still underweight though, so we shall see. We showed a picture to the lady at the tack shop and she thinks he's a draft cross based on his face size and the shape of his feet and ankles. She also said possibly Thoroughbred due to him having a slight attitude problem. I just say he's a brown horse when asked what kind he his. ;)
Thanks for the ebay
link and for the drafttack.com referral. I'm glad to see that the snaffles are reasonably priced. At least I won't be out a ton of money if it doesn't work out.