The fullness of the white – either polar bear or arctic runner or icelandic sheep depends on the fur itself and underfur. Generally, I like a slim profile, kinda like a fat candlefish (sandlance) or a skinny smelt.
FYI, I just back from landing two dollies of approx. ten pounds each on a very slim and chewed up popper.
Also, the flyshop I work part-time at has just received 300 #6 and 300 #4 dink components. We will package them in packs of six and also put together popper kits with hooks, materials heads and instructions.