Hi MaddieMay, welcome! I'm new here too - its only been a week and a half, and already I'm starting to get the hang of it and enjoy this new woe.
There's a great answer to your question about how much to eat -- if you go back to Feb. 23, its in a post called "Daily Musts? Daily Limits?" I found that answer SO helpful for me. I was feeling sick from Atkins, and from overeating fat and protein when I first started SP, and this post helped me listen to my body and eat just what I needed. I'm really feeling pretty good right now.

I haven't lost weight since on the SP yet. I gained a couple pounds and then lost them, so I'm right where I was when I started a week ago. I don't mind though. I'm finding I feel SANER than I have in years!! LOL. I'd forgotten what it felt like to feel balanced, not craving, not thinking about food, etc. There's so much else to do wtih my time.

I expect to slowly lose the weight on this plan, as my body adjusts. What I know for sure, though, is that my body will end up weighing what it needs to weigh for my maximal health. Because I'm eating what I need, rather than what I crave. I'm beginning to be able to tell the difference.