Consider frontloading the Deca @ 500mgs for the first two weeks and then drop to 300-400mgs for the next 6 weeks. I don't think you will gain much more that you will be able to keep for going 10 weeks versus 8 weeks.
wk1-2 500mgs
wk3-8 300-400mgs
Then, of course, eat and train correctly. Keep us posted what you decide and how it works out. Also, some test like 300-400mgs weekly would not hurt - full 8 weeks.
SF