I use the method demonstrated on a few youtube videos whereby you use a piece of card with a hole in the centre, place that over the left stick so that you can 'pinch' the card / hold it against the side of the controller so that the left stick is pulled to the left or pushed to the right ever so slightly to set the rotation while matching its speed with the right stick. It allows you to keep one variable as constant as you possibly can while adjusting the other to get that orbit as precise as possible.
As an alternative I am beta testing the P3 support for Autoflight Logic and it can produce some nice orbits such as the one below on a blustery day.
I think it comes down to what you prefer as you get a lot of satisfaction from the manual approach and it can be adjusted on the fly whereby the app approach does allow you to perform an orbit while being relatively hands off and perhaps more in the shot.