1. In general... Is your horse willing to walk, trot and lope at a steady, energetic pace, or do you have to keep pushing him to keep him going?
2. Does the tail swishing/balking happen every time you ask him to speed up (from standstill to walk... from walk to trot... from trot to lope), or only when you ask him to increase his speed to a gallop?
3. Are you asking him to go to a gallop from a trot or lope, or are you asking him to "blast off" from a walk or standstill?
4. When you watch him play in the pasture, do you see him galloping hard when he plays, or does he tend to lope (or perhaps mostly trot from place to place)?
5. Before you bought him, what was he doing for his job?
6. Has the tail swishing and bucking been getting worse, better, or has it stayed the same since you started working on galloping.
7. When you ride, are you in an arena with soft footing, or is the footing packed hard?
8. Does he wear shoes?
9. When you ride, do you practice other things besides your gaming patterns? Do you take days off to just go out for a trail ride now and then?
10. Have you ever tried riding him in a different saddle?