[hunter.england]

Might be a bit late to the party here but my solution was a Standard USB mouse (with the scroll wheel removed), connected to my Galaxy Tab 4 via an OTG Cable. I then attached a 22mm plastic pipe clip (used to hold central heating pipes to walls etc) to the bottom of the mouse, have the buttons facing you and clip it the one of the feet of my mic stand. You have forward and back and the touch is very delicate and instant. You do need to glance down to get your foot ready but not too difficult. I am looking at converting the mouse to something better as far as finding the button but with it clipped to the mic stand it seems fine.