Thanks for the replies! Yep, after reading this and doing some experimenting on my own I am seeing more of how these apps fit together. I am pretty sure I can customize my layouts exactly how I want them in Sculptor - I do have a couple of questions, but I will post those under that topic.
But there is one thing that I'm pretty sure I can't do in the interface - that's adding a "faux background" that scales to fit the browser window. I do have the div coding and necessary CSS to make this work - but where's the best place to add it in? I can import the layout into SAP then add it, or would it be better to make a template?