drbob1:

I've found the IOS interface clunky-hard to get the knobs to turn easily. You can assign them to x,y,z but it would be easier if tapping on any knob temporarily assigned it to the big knob! 

That's not a bad idea.  In the next release we'll probably just make the active area for the controls bigger though so they're easier to hit…  Incidentally, you do know that when you press one of the rotary knobs you drag up and down to increase or decrease the value, right?  Some people try to  drag around the knob (or left / right), but that's not how those controls are configured to respond to user gestures…