Hi Tina and Welcome!!!
Those are some great questions. I will answer what I can. First let me jsut say, I'm so happy that you found BW and are now able to read your los cues.
As far as feeding on demand, once you understand your lo's cues, you will know when she needs fed. You never have to refuse the breast because you know when your lo needs and wants it. If your lo has to feed every 2 hours, that is perfectly normal. I think the thing is to ensure your lo is filling her belly at each feed and not becoming a snacker.
As far as growth spurts, the book discusses cluster feeding which will help out well, also, you can just use a 2 hour EASY instead of the 3 hour. I found with my lo growth spurts were pretty easy because I just followed his lead.
I hope I answered some of your questions. There are other mamas on here who may be a bit more educated in some areas, especially the nursing on demand.
Enjoy the site!