Creating and Refreshing a Starter for a Specific Recipe

I am getting ready to bake Paul Merry's French country bread from Country Breads of the World by L. Collister & A. Blake and I can see that the baker builds the starter from the scratch for three days, refreshes it twice, over the following two days and then creates the dough after the time lapse of anywhere from 4 to 12 hours after last refreshment.  The built starter and the dough are 66% hydration.

My question is, since I have a healthy white starter in my fridge, 100% and ready to go, will it suffice to convert it to 66% hydration and then proceed with making the dough after the suggested time.  In essence, I would go strait to the second refreshment.  Will it matter that I did not keep the starter at 66% from the beginning of the process? And if so, what will this fact affect - rise, crumb, taste?

The second question has to do with the converter I am using.  I have this tiny Excel spreadsheet that enables me to calculate starter conversions from any higher hydration to any desired lower starter hydration.  It does it in such a way that I don't waste any starter, but build to exact quantity required by the recipe, by taking the minimum required quantity of the mother starter.  In other words, I only add flour (the amount calculated by the worksheet) for the firmer starter.  However, I am so used to adding both flour and water that it seems sacrilegious that I don't do this anymore.  Would "The French Baker" frown if he knew?

By the way, I will gladly share the converter tool if you are interested.

Gosia