Hi Fred,
I always advice to take the latest version of a certification exam. There are a number of differences between the EE5 and EE6 exam. You might want to check the exam topics from the official oracle certification
site or read some of the stories of people who passed the EE6 version of the exam lately (check the
Certification Results Forum)
I must warn you that the WSD exam is quite tough and totaly different from the OCPJP6 exam. You might want to consider doing the WCD6 and EJB6 exams first as a couple of questions come from these exams. Apart from that, for the WCD and
EJB exams reading and studying one book and some parts of the specifications is enough whereas for the WSD exam you have to gather a lot of materials to prepare yourself.
Regards,
Frits