Layer height should not be more than 80% of nozzle diameter; in this case, 0.32 is the largest layer height you should use, but you can use it for all layers.
From your photos, the issue is not the layer height, but what is caled the z-offset (the height between the nozzle and the print sheet not including the layer height). PETG prefers having a larger z-offset compared to PLA. You can most easily change this on the touchscreen when you first select the file you want to print.
As for clogs, this is the info you need to read up on, esepcially if you are going to be printing PETG or any other high-temp filament (ABS, ASA, Nylon, etc):