the method I have. been using for harvesting down from a repurposed source is this:
using a vacuum put down-proof netting of some kind over the main hose with a rubber band (I used $1/yd chiffon scrap from walmart). then attach an extension to the hose. vacuum down from your source until it stops sucking and then turn off the vac. after the vac stops running pull the extension off the hose, push the down in a bit with your finger (to get itvaway from your mouth), put it in the baffle as far as possible and blow the down into the baffle.
some points to note: be careful about inflating the baffle when blowing the down. I found that when I tightly sealed the fabric around the extension and blew a lot of down that the baffle would inflate and then it would blow the down back out the extension when I finished. also be careful not to inhale down when blowing...that is why I pack it down with my finger hefore blowing.
I end up with very little stray down using this method.