Would anyone advise against taking the server requirement tests (70-640, 70-642, and 70-643) for MCITP EA out of order? The reason I ask is because as you may know, these tests now include R2 content and MS has only released one (2nd edition) press book with R2 material (70-642). I wanted to start with 70-640, but am thinking I should start with 70-642 since I can study all material that will be covered in the exam without having to read several different books. I know the rest of the 2nd edition books are coming out within the next few months, but I don't want to have to wait.
Do I
have to take the exams in order? Is it best
to take them in order? Ideas, suggestions, or comments?

Thanks!