not a wise move for a couple of reasons. first, taking any steroid, at any dose is going to keep you shut down. dont fool yourself. if you're taking something, you're still "on". second, its not a wise idea to try to cut up right after you've gained new mass. you want to give yourself time to get used to holding this new muscle. when you come off and run PCT, you need to keep the food intake just about as high as you did while gaining. muscle isnt economic for your body. it takes a lot to your body's resources to maintain. the first thing it will want to do is drop the new lbs so you dont want to give it a reason to do so. i would wait through PCT and then an additional couple months of training without gear to work at holding as much as you can. then if you decide that you want to cut, do so with a proper cutting cycle. if you found that you put on too much fat in this cycle and thats the reason you wanted to diet down some, your diet was off. you'll need to make some adjustments, probably to carbs, in the future

there is no need to tapper the gear down when you come off. i would stop the deca one wk before the test. then 2 wks after your last test shot(now 3 wks after last deca shot) start PCT. clomid or nolvadex for 3 wks