You can also connect to the computer remotely via utilities like Remote Desktop, Teamviewer, Splashtop and the like. Set the computer to a 4:3 aspect resolution for using an iPad to remote control. Here are three screenshots taken from an iPad that demonstrate three different resolutions. The lower the resolution, the less bandwidth the connection will need.
1280 x 960 / 100%
1600 x 1200 / 135%
1154 x 864 / 100%
The last image shows some trickery in that I used a AutoHotKey script that allows me to toggle off the title bar and/or menu bar of the Totalmix FX window (it also maximized the window to whatever resolution I am currently using).
I found that I could control all elements with my finger in all three resolution/sizes, but of course the last image offers the largest elements and thus is easiest to control.
Be aware that Totalmix FX is *not* multi-touch capable, even when your OS is (like Windows 8+). So you can only control one fader, knob or button at the same time. So other solutions might be more practical.