Hi Darren,
Yes, it is possible to use our plugin to limit the maximum number of products per category per user. To set this up, in the plugin’s settings configure the following options:
General > Mode > Product Quantities
General > Date range > This year
Limits > Per product category > Enable
Then go to each category in Products > Categories and edit each category. You will find a new field for Limit per user. Set the relevant limit.
If you wish historical orders to be part of the calculation, run the Recalculate sales data option in the Tools tab of the plugin’s settings.