yes 4 weeks of deca is kind of a waste, if you want to go that route, i would run NPP nandrolone phenylpropionate, it is a fast acting ester of nandrolone.
also femara will do nothing to combat nandrolone sides, you will need dostinex (cabaser) at 0.5mg e4d
although 400mg/week for 4 weeks will probably not give you many side effects.