It's my preference not to pack the whole hub. If you pack the bearings by hand properly or with a bearing packer, and intend to continue doing that way, then there really is no need to pack the whole hub and grease passageway. It's just a waste of grease. Whenever I have repacked bearings, I have always observed that only the grease within the bearing gets discoloured. The grease in the hub that is outside the bearing always looks as good as new. I discussed this with the Dexter Tech at the rally and he concurred. Also if you consider sealed bearings, then you can appreciate how little grease a bearing actually needs.
On boat trailers that see axle immersion, then packing the whole hub with grease is a good idea to keep water out.