This is a much used guide to what your eyebrows should be based on your face shape. You should get whatever thickness you like, but that also depends on how your eyebrows grow in.
I'm planning to get my eyebrows waxed for the first time, I've gotten the middle on my nose waxed but never had my eyebrows shaped. How do I know what shape and thickness my eyebrows should be?
You might be better off going for eyebrow threading, or you might end up like this:-