Rob,
When you get home from work please measure the overall length of your model as she sits.
From Wikipedia the overall length of the Great Republic was 334'. The length "on deck" was 325' - see here:
http://www.loc.gov/pictures/item/90716149/.
Her overall length (presumably including bow sprit and whatever may have extended abaft the stern) was 400'. See here:
https://en.wikipedia.org/wiki/Great_Republic
Not that any of this matters in viewing your wonderful work on this project, I just thought that the scale you mentioned earlier must have been off based on what I was seeing in your posts.
My guess on the length of your model as it now stands is around 30" which would make it, based only on the measurement from stem to stern (which is, of course, longer than the deck measurement) a scale of around 1/135 (+/-). In any case it's going to be a very impressive model indeed. It'll also be big enough to allow you to rig her without using ultra powerful magnifying lenses