I'm getting ready for my next test, 4th kyu, as well and I have been nervous about how I will do. I stopped worrying the other night when I talked to my sensei. He eased my anxiety by telling me that I'm almost ready for 3rd kyu. With that anxiety gone, I have been able to relax and just concentrate on being mentally prepared for the test.
It sound like you have done all your background work. The key now is your mental focus. Having done the usual repetition of practice, I have found it easier to keep myself relaxed and confident.
Just have the faith in yourself that you will do well and you will do well. Don't fuss over mistakes during the test, just keep going.
Right now when I'm getting ready for bed, I will visualize myself doing the test.
Other than that since you have done the practice, I don't know what else you can do.