The first bobbin is wound with as much thread as it will carry. The trick is not to load the bobbin with too much thread which makes the thread wider than the head. This can cause the thread to skip over the head and get tangled. The second bobbin I wind only the top half of the neck, usually with a meter or less of thread. This is usually enough for my designs, leaving me with only one bobbin with waste thread on. The full bobbin simply refills the empty one as needed.
The hitch uses two loops around the neck.
Different bobbins, thread weights, twists, thread content, and plies can call for different hitches.
Do not be concerned when I say I drop the bobbin on the floor, I am not smashing the beads on ceramic tiles, or throwing the thread into muddy footprints! There is a special little quilt just for the job, I wind so many bobbins, that this gives me the fastest way to measure. Here's my rough guide.
Drop from the waist - sitting = 60cm
Drop from the bust - sitting = 90 cm
Drop from the waist - standing = 1 meter
Drop from the bust - standing = 1.25 meter.