i read somewhere on here that if you use a compression bag you can get it much smaller, maybe i'm wrong though.
I always try to use the manufacturer's stuff sacks when possible, and when using compression sacks I don't get too crazy with it just to say "look how small this thing packs!" - to take it easy on the down.
I don't like the extra weight of the compression stuff sacks. How about going with a cuben pack liner and just stuffing the insulation down in the bottom of your pack. Saves some weight, conforms to all the nooks in your pack, and is water proof. I put my cloths bag in there as well as anything else I don't want to get wet. YMMV.
"When you see something wobble, push it."