QuickClose put me through the Five Stages of Grief. First, Denial that the way this works (a slot type for outside the GUI) has existed since 1.8! Second, Anger stemmed from not having thought of this first. Third came Bargaining with myself - surely someone else had thought of this before? Fourth, a harsh Depression kicked in when my search results came back empty. Lastly, warm Acceptance as I downloaded the plugin. No regrets!
Works as described, very handy little Quality of Life I will be adding to all my servers. Barely shows on timings and in my testing I set the click amount to 100 and it accurately tracked and closed the inventory.