So speed of throw doesn't matter so much as consistency of throw?
I operate my Uniflow briskly with a definitive sounding tap at the top, and on the down stroke. Some folks use two taps, I use one, but the important thing is to get in the groove and be consistent. Tap with the same amount of force each cycle. It's noteworthy to mention giving a pause at the top of the stroke to allow the powder a moment to flow and fill the cylinder. The larger the powder charge, the longer the pause.