Parametric, Customizable Phone Stand

Hold the phone in the intended orientation for the stand (usually portrait format) measure its dimensions (mm) and put them into the appropriate fields in the Customizer window.
For most people that is enough customization.
The other values affect the shoulder widths between the phone and the base edge, rounding off of the sharp edges and the aesthetic of the ratio between phone height and base height. Feel free to play with them but they can be safely ignored.
P.S. Don't forget to measure with the silcon cover in place (if any).
P.P.S. It is also a good idea to inflate the measured values by a couple of millmetres to get an easy fit.