Hi

Statistics can take max up to about 200 rows of data, which means they are tiny in terms of size.

I think you cannot know which statistics were used by the query optimizer. As you say you have additional statistics (not the indexes' ones) you can make a check to see which of them are already covered by the indexes' statistics. In any case multi-column statistics can be useful to the query optimizer. Maybe you can eliminate some of them and not all.

Regards

IgorMi