Currently studying my diploma and trying trying to find a source where I can find information on typical rootstocks used in different regions, the Medoc for example and how producers go about clonal selection in different regions.
A bit of a warning. I am currently taking a viticulture class at Napa Valley College. The teacher is a graduate from Davis with an MA in viviticulture. And in regards to your question about rootstocks, it might be helpful to know one thing she stated. I was surprised to hear her say that different countries not only develop their own rootstocks but also that even she would not recognize or know anything about most rootstocks developed in other countries. Considering that she is a vineyard manager in Napa and has a MA from Davis in viticulture, I found this striking. It seems like even vineyard managers' knowledge can be restricted to the rootstocks developed and in use for their own countries, at least to a considerable degree.
When she went over rootstocks in class, she spent more time outlining the parents used to create the commercial rootstocks. Since the commercial rootstocks in use acquire their properties from their parents, knowing the two parents of a rootstock will provide a rough sketch of the properties of any rootstock. To my knowledge, this principle should roughly hold for rootstocks developed in any country. There are only something like 6 roostocks used as parents, so this helps provide a system of being able to state the properties of a particular rootstock hybrid.
It sounds to me like some of these classes are asking questions that might make a vineyard manager scratch their heads, why the question is a better choice than another question.