I have looked at all the midi data in OSCTouch editor, they all start with xF0, That means they are all SysEx messages, why is that, Should some of them , e.g. Patch change can be CC or PC message instead?
If nothing else, you can get some mileage out of copying the CC Message faders and XY pads to your own template, and moving those simple messages over to the MIDI tab on each control. These can be used with the Assigns in the GR55 to control quite a few things. Unfortunately, I don't think patch navigation is among them.
But things like pickup selection, amp selection, etc. are, and if you experiment you can begin replacing these sliders with distinct buttons that call out the components/ positions (i.e. the specific values) you prefer, which could be very useful in performance.
I've said it about a dozen times already, but I think one of the most exciting things about these iOS interface apps (TouchOSC, MIDI Touch, etc) is that everyone can wind up with a UI that exactly suits their own personal preferences.