Hi, it's perfectly normal for the slave pedal to sway less than the master pedal. It's an unfortunate reality of double pedals. Even my speed cobra slave sways much less freely than the main pedal, however both pedals actually feel the same.
Also, I can press the left hand pedal down a small portion without the beater actually moving, due to this extra movement in the drive shaft.
That is not good at all.
Trick Drums makes possibly the best pedal drive shaft in the world, and the 5.0 version is available in retrofit that works perfectly with most or all other major manufacturers' pedals. It's a great investment. As far as I know there are two models, each which is designed to work with a number of other pedals. Just get the correct one and you'll be all set.