That can be a tricky question.... we usually recommend .7 to 1 full ounce of FO in CP soap.
However, a lot of fragrances are stronger or weaker than others so it can depend! If you want a softer smelling soap then maybe try .5 to .7 oz per pound? I usually make mine on the strong side though so I personally have not used that little before.
Fragrance free soap is great too! A lot more popular than some think!
You can always make some smaller batches... 1 or 2 pound sizes to kind of test out the strength. Check out how to rebatch too, that way you can go back and add more scent if you want stronger or add to more soap if you want weaker.