Arthur,
It is hard to give a simple answer to your question. In my experience, it takes a fair amount of yeast in a dough to have it rise two or three times (usually with punchdowns in between). However, with the right amount of yeast, the doubling or tripling of the dough can take place at room temperature or under cold fermentation and it can happen over the course of a few hours (e.g., for a dough fermented at room temperaure) or over a period of a day or more (e.g., for a cold fermented dough). In general, commercial yeasts tend to produce doughs with greater and faster volume expansion than when natural starters are used but if the amount of starter used is fairly high and it is also highly active and the dough also undergoes some period of room temperature fermentation, it is possible to get a similar dough expansion from the use of natural starters. Some members supplement natural starters with commercial yeast to get increased dough expansion just in case the natural starter can't do the job alone, especially when the amount of starter used is very small.
I personally don't equate multiple dough rises with quality in the finished crust. The dough might be light and airy but the flavor in the finished crust may be lacking because of insufficient fermentation. High amounts of yeast also use up sugars faster, which means you will usually use the finished dough sooner. If the window of usability is too short, there may be insufficient time to develop the byproducts of fermentation that contribute to crust flavor and odor. In my opinion, the only time to use high amounts of yeast and multiple rises is when you want to make a few-hours (a.k.a. "emergency") dough. You will get a light and airy dough in most cases, but at the expense of a flavorful, well-textured crust.
I am familiar with the post you referenced. My recollection is that Marco indicated that you have to get to really high levels of yeast, around 5% or so, before the natural sugars in the dough are depleted. I am not aware of any dough formulation that calls for that amount of yeast. Under normal circumstances you shouldn't need any added sugar in your dough, however, many people like it for flavor purposes and better crust coloration. In your case, with a very high temperature oven, you will not want to add any sugar to your doughs. The high oven temperatures will cause the sugar to burn and blacken the bottom crust.
Peter
