Hello,
It is perfectly possible to use touch screens, in fact in tablets and iPads everything is touching.
In my setup I have 3 touch screens on same computer plus an external tablet.
The buttons and the knobs are operative and there is a virtual keyboard to enter values.
The knobs functioning depend also on the touch screen or tablet quality and resolution, there are some cheap tablets where is almost impossible to use a knob because the touching quality is very poor.
The last thing to mention, and this is fun but true is about fingers, I know a user with huge fingers and he is not capable to use the knobs.
Since you have the demo version, feel free to use it before paying and you will know if that really works for your device.
Thanks!