I don't know if this will help but I used to get all the colours cut and defluffed and put into individual piles on the desk and then just take a pinch from each one. I would then drop all the pinches, tip down, into a shot glass to get the length right, scoop them out and offer them up to the hook.
I thought about getting a whiskey measuring gill and taking a hacksaw to it to make the same kind of scoop but the shot glass work so well that I kept using that.
The glass thing works with squirrel too.
Oh and Ben, the glass has to be DRY....