You said "unwanted BF"....How much? If you are up at 30%, or something like that...then I would say to try an extreme diet and plan your cycle for it...Tell yourself that "I gotta lose X amount of BF by a certain date...then it may be push for you to get it down in time.
Otherwise if you have been working out and already have a good muscle base, and you don't want to lose anyof it while on a colorie deficient diet....Then I would say go ahead and start the cycle.. Eat as clean as possible and the fat will still go away but your muscles will stay and if you eat enough PT then you gain muscle to.
I have never tried Deca and don't think I will. But if you want to use it...and don't want too high of a dose, You may want to consider a 10 weeker of 1cc Deca, 1cc Test E5D...it will average out to 280mgs Deca & 350 EW of Test...So you will need 2800mg's of Deca and 3500mg's of Test to complete the cycle.
If that aint high enoough for you go E4D with the same amount and you will get 340mg's of Deca and 425mg's of Test EW over a 10 week cycle. which you will need 3400mg's Deca and 4250mg's of test to complete the cycle.