I have one of those. They are warm as toast ( to get into tech talk)
Be aware that the "down" has (IIRC) around 20% feathers.
This will affect compressibility.
A rodent ate a hole in mine so I am also contemplating making a Top Quilt.
About removing the down:
The method involves a shop vacuum and a piece of fine netting. You suck the hose full of down and then reverse and spit into a bag. Again, from memory, so details are suspect, but a search on the archives should yield a first hand report.