Don't be so set in what your RTH altitude is 'set' at ... This should be something you do in setting up for each flight based on the terrain you are flying over.
Due to wind-speed increasing with altitude, and the Mav' Mini being famous for not handling wind well

- my suggestion is that you should look for the tallest obstacle around you (e.g. fence, tree), and set your RTH altitude to just clear that. Doing so will minimise the chance of the MM popping up into faster air if RTH is invoked. For the same reason, it is best to train yourself to fly home manually, and if coming home is flying into wind, then get the MM down as low as you can safely fly it.