Cinny, I don't want to sound as an evil advocate or discouraging, but how do you know he schools 1st level (or even 2nd)? Do you have a good trainer telling you that or you just feel/guess? I started with my qh last year (both knew nothing), and we are not nearly close to the 1st level. Just went through Intro and Training 1 this summer. Now I have no idea how experienced you are as a rider, but personally I wouldn't try to jump to the higher levels, but start with Intro and see how it goes. If you get high scores then you can just progress through the level fast.
I don't think you sound like an evil advocate at all, your question is well grounded.
Last year we did show schooling shows at Intro Level with high 50's. Since then we have worked on our holes. I've had other people at my stable who ride dressage watch and give some hints now and then about what is good, what is bad about our rides.
There is a website geared towards mainly dressage riding that is run by some pretty prominent trainers and clinicians. I can't link to it so you can see it because it does have a message board and that's against the rules here. Anyway there is a training area with a checklist that you go through for each level. You can mark off how well your horse does something whether it has just learned it, is schooling it, or accomplishes it well, etc etc. You can see what things your horse has to be able to do in each level. It doesn't just say what your horse should be able to do for the tests, it has other exercises for building muscle, brain etc too.
Anyway, we are working on many of the 1st level exercises and accomplishments. A well balanced 10meter circle at working trot (sitting). A well balanced 15 m circle at canter. Light serpentine work at walk and working trot. Shoulders in/out and haunches in/out. He actually has a really niced 10m circle trotting with shoulders out (I'm so proud). Leg Yields. I think most of these are 1st level and our workouts usually are on this stuff because, well, it makes Cinny happy to work on this stuff instead of Intro stuff which seems to bore him to insanity.
I'm hoping to get some vid up soon of this stuff, but I have to coordinate with my DH LOL.