I generated a temperature tower to assess the right settings for various materials. The idea was to try bridging, holes, fillets and chamfers.
I used Slic3r's "After Each Layer" code capability to change the temperature every millimeter of height automatically. Starting at 260C dropping to 190C. I stopped the print at 200C because it was clearly not working at that point.
The material is the cheap Amazon PETG. It looks like 250 or 245 are best for that material.
Link to the temperature tower. https://a360.co/2SMtNR6
I'll post the gcode later when I figure out where to keep it in the cloud