Hi,
The short answer is yes if you expect all those documents as a result of one query.
This parameters are related to search results rather than number of documents in your repository. You could have 10 millions of documents in your repository but if your search queries return no more than 1000 nodes at once you won't need to set the maxPermissionChecks to more than 1000. Alfresco checks permissions for every node in result set and not for every document in repository. It means if your search returns 10000 nodes and maxPermissionChecks is set to 10, at the end you receive the first 10 nodes from the result set for which you have enough privileges. Of course, you have to give Alfresco enough time to check permissions - maxPermissioncheckTimeMillis.
Regards,
Blaž