Hi! I´m a Java Certified and I have experience teaching and preparing other students for certification.
I don´t know exactly what topics you are interested in, but my idea is to prepare at least 1 video for each Java Certification Unit. Some units may have more videos because they are more difficult.
Also we can prepare some videos related to the development itself,like tools or frameworks (Eclipse, Net Beans, etc), Application Servers, Maven, Spring, ubuntu, windows, etc. There are a lot of options to create an excellent training.
Since you posted "at least 200 Questions", I´m thinking about 20 videos, and each video needs at least 45 min of work. (around 15 hs)
Let me know any further questions,