These can be cut into 2 parts or 4 parts and glued together if you want a bigger size. Scale to bed size, can raise the height if you want it to stick out more.

0.4 Nozzel
0.25 Layer height
2 Walls
2 Bot layers
2-3 Top Layer
7-15% Infill

These are my settings may not work for everyone, I use Black PLA don't see why it wouldn't work with PETG

Also added my g codes from my print, use at your own risk as I'm not 100% how they will work on other printers. I'm using a AnyCubic Kobra