I do this in every one minute because I wasn't sure about the load of the command at that time(seems minimal though). Should have no problem to run it on every touch.
and mouseturn is different from evdev as it relies on /dev/input/mice so it's plug&play, sth. like
this.
And if you have multiple devices you can run multiple instances of kindle-evdev or try this updated version. it goes like
kindle-evdev2 -f /dev/input/eventX /dev/input/eventY ... -c key1:x,y key2:x,y.....