Okay, its real easy, 500 or under on your DD, no 2 DD s together you need to be fuelled before undergoing a DD, 1500 is not enough on an UP day , its too low, you need the swing between feast and famine , 500/2000 is the general rule of thumb that works for the majority, DD are the magic days so do your best to stick to them , don't worry too much about going over on your UP days I regulary do lol, You can do 2 UP days if you like a lot of us do set DD s usually M,W,F as DD then UP t,th and sat and sun, and still lose weight its a fairly forgiving diet. The most important thing to remember is to stick to your DD cals and you are not dieting on your UP days so eat your cals , good luck.
I have been Juddding now for 18 weeks and can genuinely say it has changed my life and relationship with food forever x
ETA you can up your DD cals after the induction phase (during which you can eat any foods doesn't have to be shakes just make sure you know the cals of everything you put in your mouth and don't forget to count in your milk !) but as 500 and under are optimum for weightloss I don't know of anyone who has , the DD s get easier as you go along and you will find that you can get by just fine on 500 or under x