Thanks for an extremely useful app. I worked my way through the need for a good fix first, and only try and stop recording when I am certain I have had the green record button light up for more than about 10 seconds (2 readings at 5sec intervals).
I do find, however, that I have to close the application between recordings, otherwise the track is deleted. This means, the first recording is saved, but if one starts a new recording (after waiting for a good fix) and entering a name for the track, the new dataset is deleted on stopping.