If you do the Dr. Clark method, you can eat until 2pm (if you start es at 6pm) I always start later myself but you do need to stop eating atleast 4 hours before you start. As far as quantity, I personally don't control portions, just eat no fat. I drink as much water as possible while eating and although I don't drink quite as much, I continue to drink water all evening. I know some people don't but I also get dehydrated and get headaches if I don't drink water. It has not seemed to effect my results. Infact I chase my doses of es with atleast 6 oz of water.
As far as apple juice, I am not an expert. I have not tried the apple juice thing. I've only done Dr. Clark. My only modification of her method is that I seem to do better with 3/4 c oo instead of 1/2.