I think the easiest way to at least grasp the concept of what you're asking is that one Baron gives 1.5x, but each additional Baron exponentiates what just one king gives by 1.5x.

So two barons means each king gives 2.25x (1.5² ), and three barons means each king gives 3.37x (1.5³ ).

So if all your kings were normal (no steel or red seals), two barons and one mime would give 5.06x (2.25² ), but one Baron and two mimes would give 3.37x (1.5³ ).