Try these two books

Slave Trading in the old south by Frederic Bancroft.

Speculators and Slaves by Michael Tadman

These will explain which states provided Louisiana and South Carolina with Mulatto(Correct term for the time) women, men and children of long and short pedigrees of white ancestry to command the highest price.

Class is another word for divide. Each divide must remember from whence they came. For all came from the same kettle.

Quan