Binding angles are useless metrics without knowing board width and boot size. I would always put my rear boot in an angle that is as flat as possible without having boot out. On a race board, you can have a little bit of boot out if you're riding a narrow board (19cm ish wide), if you want to do recreational laid down carves, allow no boot out at all.
So my rear foot would always be set up automatically in this way. Now you have to add a little splay (most of the time). You have to find that out for yourself, but most people have about 5 degrees of splay. For myself, at the moment I ride with 7-12 degrees of splay, since I'm a bit bowlegged. A bit more splay when it's a wider board, a bit less when it's a narrow board.