Does being left handed put you at a disadvantage when doing the 2 handed co-ordination test?
Unless its changed recently the test is far more to do with testing how quick you correct an error (going outside the lines) than the amount of times you make that error. As said previously its nothing like a computer game controller-best practice is an old Echasketch!
The practice material really doesn't help as those tests make each hand work to two different exercises. The test is about getting them to work together. I took it today, I was making it beep A LOT! But corrected it very quickly and I have passed that particular test with high marks apparently. I don't think there is much you can do to prepare really, if you can do it I would say you will pick it up pretty quickly on the practice goes.