Did you look at the help topic if you press Help or hit the F1 topic in the dialog? It has a lot of information there. Generally, the angle tolerance means the angle deviation between the flat faces that are generated in the STL and deviation means the distance between the modeled surface and the flat surface of the flat face generated for the STL. Your best bet will be to look at the preview that you can get within the dialog. Also, you may have to do some trial and error with making some sample prints of portions of the model since different 3D printers produce different results based on the printing method and some printing techniques are more forgiving on the input data than others.
I hope this helps,
Your kind answer from various aspect helped me a lot!