I have a recipe for Greek butter cookies that does not use any salt. I like to add salt because I think it brightens food.

The recipe uses 8 to 9 Cups all-purpose flour. How much salt should I add to brighten the flavor but not overpower the other ingredients?

Salt to flour ratio would be important when making bread; but... you won't need salt in your greek cookie dough. If you want it I would add just a teaspoon of salt, which would suffice.

The ratio for cookies is 1-2-3, 1 part sugar, 2 parts fat, 3 parts flour. I believe that using some good company ingredients will be helpful to replace them. Nowadays there are many companies selling good food products that are natural like Sheffafoods– you can try them out.