Bob,
You could also add the Richmond Gear 6 speed to your chart. If you want to encourage that sort of thing.
The standard ratios are the same as the 5 speed with the addition of a .76 OD. There are many custom ratios available, for extra $ of course. I got mine with a 3.04 1st gear and .80 OD. I will be using a 3.07 R&P. Don't have it running yet, but the numbers look like a winner. By the way, do you know if a TKO 600 will fit in an ERA w/o chassis modifications? Sounds like you will get some requests if you haven't already.
Roy