Dhurwitz,
I guess you could consider it like this. The classic "average" is about 55 miles per day OVERALL (includes all days, riding, resting, long, short, etc.), not riding average. If your OVERALL average, again not riding, is 75 miles per day, then you could just figure it based on that.
Honestly, I think you are over analyzing this. The more important factor is where are the overnight stops. As I pointed out earlier, even if you could do 100 miles, you may be forced to go 60 or 120 in order to not stealth camp and/or stealth camp in a place that meets your needs. Since you appear to be a relatively strong rider, if you get behind by a day, you could easily make it up sometime in the next week by riding a couple of hours extra for a few days. Don't sweat it too much.
Also, I would assume your first week would have lower mileage as you are getting adjusted to it, i.e. breaking camp efficiently, having the body get used to it, etc.
As a final note, whatever you plan out will most likely not happen in reality. You will be off on some days and you will be where you planned some days. In over 35 years of touring, I have never had a tour go exactly as planned, regardless how long or short the tour is. You can't plan for delays due to severe weather, major mechanical issues, getting sick, etc. You can build in a few "buffer" or extra rest days to help but that is about it, nothing guaranteed.
Whatever you do, I hope you have a wonderful trip! John