I am not surprised you went into sticker shock over Dream Orient. Any Silk or silk blend batting is going to be VERY expensive. Silk is lovely though. It has unparalleled drape which is why it is often reserved for quilted clothing. It is also fairly flat (very low loft) so the quilting won't stand out very much. It is breathable and considered a medium warm batting(temperature wise) Silk is very luxurious and expensive.
Edited to add that CT currently has the silk on sale at 30% off. This silk does have a % of poly.
http://www.connectingthreads.com/bat...HobbsSilk.html
W&N is very heavy weight wise. If you go cotton or cotton blend go with Quilters Dream or Hobbs 80/20, much lighter in weight than W&N
I think this website and the chart I have linked to will help you a lot
http://thecuriousquilter.wordpress.c...atting-basics/
http://www.scribd.com/doc/37522922/C...rt-Copyrighted