The Ipilot records track points. Track points are relative to position, not time (speed). So, any speed in theory should work. However, I found if you go too slow when recording a track, the unit becomes somewhat erratic (below .5mph) when you use trackback .

I got the 3 track unit. Keeps me busy trying to remember what I did last time out.

I use my big motor when recording sometimes. Saves electricity.