I have had alright luck using MIDI Designer for ios and the "camera connection cord" that pretty much lets you plug usb into your iphone. I have a template that I was working on, but its unfinished. I have had trouble with the gate length parameter, changing midi channels and setting up pitch bend range. I'll see if I can figure out a way to share the file here. The app is pretty cool. It seems like you can do everything in the free version, it just has really annoying ads.