James, just build another gun, will ya? Each one will get better until you can't see anymore and then they start to get worse, gun by gun.
Practice is the mother of something, and you are well on your way. If you can't get you hands on originals, you should try to get some good books. It looks like you do have some good material already, judging from the quality of your designs.
Also, keep your eyes and ears open for original work to study. Most collectors love to share their collection with you if the see how serious you are about your work.
If you are worried about the technical aspects of carving, a class will certainly help. But at your level, I'd think an intermediate or higher would serve you best. Sometimes Ron Scott offers carving classes. Jim Kibler has been known to teach a class or two. The WKU classes are also a good source. Those classes should be listed in Muzzleblasts in the next few months.