Spraying App

Not sure if this is the right place, but I will ask anyways.

I am looking for a mobile app to download and or buy that will work best for spraying and spreading fertilizer. I have some hay fields that range in size from 2 acres to 20 acres and I have a smaller 3pt hitch sprayer that I would like to start spraying myself, especially on the smaller fields. I have seen some apps that show basically position and passes and overlaps. any thoughts? it doesn't need to be super accurate, but its better than guessing or buying a foam marker kit. im a small operation and just wanting to try and better myself.

thanks.

Spraying App