Longer acting esters should typically be run longer.
That being said, there is an overwhelming amount of people who ran that cycle for 8 weeks and got great results. Typically these are the people that respond quickly and acrue most of their gains early in the cycle. I am one of these.
You will have to wait and see how you respond. My advice is to plan on 10 weeks. You can always stop at 8 if you choose (don't know anyone that has though but if you find that you didn't gain much beyond the initial 8 you will have learned something about your body's response to anabolics and longer esters).