High quality down consists of as little feather content as possible. The principle constituent of high quality down is termed down clusters - which slightly resemble the fluffy dandelion in seed, rather than a feather. Sounds better when you use the more accurate terms.

Have you looked at the www.backpacking.net/makegear.html site yet? I think I got that right. Go to the TLB home link way down on the bottom right of this forum page and click on that, and there will be, down on the right, a link to making your own gear. There are some suggested books there as well.