I've also found that it's better to fess up and say "I'm sorry sensei but I don't know" than to try and BS my way through something I truly didn't know. You will not fool the people giving the test, they have seen it all before
Do not try to impress the test board with speed. Correctness and control is what they want to see (at least at our dojo
Problem is with the Uke speed is it not?
If you dont get a chance to practice with them so they know how fast you go.