So, based on your quote, this index has a COMPLETE list of heads of house for 1790! There are so many states without the 1790 census in existence because it was destroyed for one reason or another. So, that means that 1790 census is not destroyed?!
Have I confused the description? Does it list heads of house only and no other data? Why, if this exists, has it never been put online or included on Ancestry.com or any other web site?