You could use a packing tool but I find that using your fingertips really lets you know how packed it is without damaging the job. Its somewhat akin to how wearing gloves lets you know exactly how well you are doing something with your hands.

Try both but I will bet you'll feel the same way and use your fingers.

Great job on learning to spin hair. Its great for so many flies and it impresses tiers that have yet to master it!

J