Given that you're already familiar with SkyDemon and already use the desktop version, then it's a logical solution.
You can pay for the 'navigation' upgrade, then load it onto a cheap 4" or 5" GPS unit which can be bought for well under £100. You shouldn't have any difficulty mounting such a unit in a Pitts.
Iv'e been looking at a cheap Chinee 7" automotive GPS to do this with.
This has an A/V socket. Any-one know if this could be used to plug in a camera & see the camera view on the screen? because it is impossible to see the camera screen in sunlight.