No expert here, but I do a lot of spinning at the bench, none of which is the result of the dram of Holy Peat Water that usually sits next to my tying table.
Here is an easy & inexpensive packer tool.
Get a "plug" from an electrical outlet box those little round circles that pop out), file the rim to a smooth finish, drill a hole about 3/16 with you hand drill, (or buy a washer with a small hole in the middle)
Get a brass case/empty shell from a hunting buddy, like a .308 or that size.
Weld the washer/plug onto the shell casing using regular welding material of household variety, something like an electric welding toll works just fine .
Voila, you can make all sizes you like, to get to pack your deer hair!
As for hair selection, a lot depends on the size of the body or head you want to make.
If you know someone who hunts deer, ask for a full skin, which is often thrown away. You will find that flank hair is different from top of the back hair as it is different from neck hair. Also, if you can get hair from young yearlings (where legal) you will find the coarseness varies. Tanning a hide would cost about $35 and you and sveral friends can have hair for years to come.
As a general rule, here is my recipe.
Back & neck hair, larger & longer & coarser hair = bass bugs & bombers, up to 3/4 inch in diameter
Flank & thigh hair, usually not as long or coarse = Spun heads (most sizes)
Upper leg hair, usually very fine = smaller spun head and ideal for "shaving" as John has described
Yearling hair (where legal) = ideal for making flared collars on small to medium sized spun head that call for a "collar"
If you don't like the razor shaving technique or clipping with scissors (they get dull real fast on dear hair), ask your friendly hairdresser for their supplier of hair clippers. I get some real neat "used" clippers for about $10 and they work just fine, some are as small as 1/2 inch wide.
Hope this helps.
Pete AKA Frenchcreek from Calgary