There is a whole group of us working on Jane quilts right now. We had lots of discussion about foundations. You might want to read through the first part of this thread. There is lots of information about fabric, foundations, etc.
http://www.quiltingboard.com/t-28063-1.htm Then scroll down to the very bottom and click on the virtual section for the Dear Janes and then mark that so that you can see all threads! We'd love to have you join the rest of us so we can pick your brain about how best to do the blocks also!
The software itself also has tons of fabric information...go to Jane Home and explore in that area..it tells you how much you need.