yes you can take the CDP tests as many times as you want. However, i would spend a lot more than 2 days on it especially if you are like me and struggle with PAT. I used the 10 test version and did only 1 each day. but after i finished the test in an hour, i took at least another 30mins - 1 hour looking over the right answer for each question to reinforce what i did right and catch my mistakes for what i did wrong. going over the answers (both right and wrong) IMO is just as important is doing the test itself.
My suggestion would be for you to spend 4 days total (if ur short on time). First 2 days divide up the 5 tests however you like and go over the answers and everything. Then give your self some time - as much as possible - 1 week, 2 weeks, 1 month whatever you can afford - and then redo the tests again after a while. this way you won't remember the mistakes you made the first time, and you can check whether you actually learned anything from your mistakes from the first time.
Gluck
