The optimal layer height will differ based on the output of a used nozzle. As starting point 80% of the nozzle size is valid in desktop 3D printers. Having a 5 mm nozzle attached we started testing with layer heights of 4 - 6 mm according to this code:
In the following tests the marked points indicate the location at which a layer height step occurs.
Test 1: results show good quality at a layer height of 6 mm (right). At lower layer height the material is flattened by the nozzle, resulting in tearing of the material.
Test 2: Layer height are set at 6 - 8 mm. The layers on the right is found to large; at 8 mm the layers prevents bonding. Also at 7.5 mm the first sign of inappropriate bonding is shown.
The optimal layer height was found at 6 - 7 mm. Further testing with the 5 mm nozzle will be executed at a layer height of 6.5 mm.