Honestly, my only recommendation is: don't apologize. It seems like your novel is unique in its reverence for historicity, and it should suffice for you to say, "to the best of the writer's knowledge, this is how Life was". I can think of absolutely no reason why it should be any different, since any culture alive today might very well pale before that same grandeur which has inspired you and countless others who have come before you. The most you can hope for is to be moderately accurate historically and grammatically; all else ought to fall naturally into place, since our debt, as cultural archaeologists and historians, is to the Past, and not the other way around.
[({R.G.)}]