I made a lid for my mortar because the hard spices were popping out when I use it.
The top diameter of my mortar is 119mm and the lid is perfectly sit on it with 0.1mm tolerance.
I recommend to measure your mortar first and adjust the size accordingly.

Creality

Ender 3 Pro

No

No

0.28mm

40%

The lid is 3.08 mm thick (11 layers high).

I also recommend the "Ironing" function in Cura. It gives a really nice smooth surface to the top layer so you don’t have to worry about spices accumulating between the lines.
Use the provided sample to tweak Ironing.