What is the proportional division schedule for a husband with multiple wives of free and slave status?

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The right of a free woman is one night out of every four nights, according to some scholars. The stronger opinion dictates that the right of a free woman is two nights out of every eight. Consequently, the right of a concubine (slave wife) should be one night out of eight to be half that of the free woman. If a husband has three free wives and a concubine, and he allocates seven nights based on the free wives' due, the eighth night presents a dilemma: if given to a free wife, she exceeds her due; if given to the concubine, she is equated with the free woman. The preferred ruling dictates that this eighth night is his to use for seclusion or to begin the cycle anew with the first wife. If he has one free wife and one concubine, they share nights out of eight, leaving five nights for him. If he has two free wives and one concubine, they share five nights, leaving three for him. If he has two free wives and two concubines, they share six nights, leaving two for him. If he only has one concubine, she has one night and he has seven, although another opinion states she has one night and he has six.