HQ Proxy Tools is a free 3dsMax script that helps you to adjust some settings of proxy objects. This script supports Vray render and Corona render.
Highlight features:
MAKE INSTANCES SIMILAR PROXIES: proxies have the same .vrmesh file or .cgeo file will be made instances. It will save memory and render faster.
INSTANCES TO VRAY/CORONA PROXIES: convert objects to vray/corona proxy and maintain their instances (The original proxy export from Vray will convert objects to proxies but also make them unique objects, which will increase your file size and render slower)