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That might depend on the formula of the soap.
M&P is very practical but with a lye soap you'd have more choices formulating yourself until you like it.

Don't worry, that will pay off for generations.

Rule of the thumb for lye soaps is one ounce of scent per pound of oils.
Since yours is M&P, you might go with 2/3 of an ounce and you'll be fine.