You want to make sure first of all the wind is minimal (look on UAV Forecast app) also if any wind at all make sure your going against the wind on your trip going out. That way you know your return trip will use less power and less
battery to travel the same distance. Then, depending on your comfort level (at your own risk) turn around even in the mid to high 40%
battery range. Until you get to know the limits - 50-55% is smarter as you mentioned above. No one wants to lose your spark - especially if over water like I was most of my flight.