Thank you Robert, I'm very happy to hear you say that I've improved

. Your tip about holding the heel knot really paid off.
The camera issue is mostly because I prop it up against something then misjudge where it's actually pointing when I take a position. Might enlist someone else's help just to make sure, next time.
As regards the extra movement, I think it might be the whip to be honest: I don't like to blame my tools as a rule, but I've noticed that I manage much more smoothly and straight with a bullwhip. My guess is that since my stockwhip's so nose heavy, and the extra movement afforded by the keepers, it likes to wobble about more. When I use the 8ft bullwhip my handle stays better aligned and cracks tend to be easier.
It's probably just me being a new cracker though :P. Thanks again for your help and advice Robert.