are the results shown in the association.ftl template limited to 1000?
Could we configure it to a larger number?
<field id="packageItems" set="items">
as suggested at https://issues.alfresco.com/jira/browse/MNT-7108, and the results where limited to maxSearchResults only when it is lower to 1000.
of a field in a form of our custom aspect,
we have created an aspect on documents, were users can associate one document to another.