The iPAd app is not intended to replace a surface.
It is a tool for settings in places where you do not have a surface. Especially in the soundcheck you can use it to adjust monitor paths or adjust the loudspeakers of a delayline perfectly.
If you need a tool to replace a surface, you have to use the Director software. This is not so easy with the iPAd, you would have to remote control another computer with the iPad. It’s easier to take another tablet to run the Director on.
The best method is to use a Windows tablet to remotely control another computer via RDP, because then you don’t have to reconnect every time you lose your connection (not impossible with WiFi!).
I don’t need the iPad any more since I’ve been doing this.