Howdy Irwin! How are things?
Not to say that you are mistaken, but I think that while a wine from a mediterreanean climate would have a lower level of tartaric acid than a continental wine, the process involved in the emergence of the sediment would still be the same. As such I really don't think there is any reason to be worried whatever the origin of the wine. Sugar is only indirectly a factor in the equation, as a high level of sugar requires a high level of acid to counterbalance it.
BTW, in Swedish we call the crystals "vinsten" signifying "wine stone", but then, we only ever knew how to make beer.