ACESproxy is not required to monitor on set with ACES. You can bake a combination of an IDT, the RRT and an ODT into a LUT and use that to monitor with an ACES base look. This can be done in a number of ways. For example, here is how you would create a LUT for Rec.709 ACES monitoring of LogC with OCIO:
ociobakelut --iconfig ~/Dropbox/OCIO/OpenColorIO-Configs-master_103/aces_1.0.3/config.ocio --inputspace "Input - ARRI - V3 LogC (EI800) - Wide Gamut" --outputspace "Output - Rec.709" --format iridas_itx --cubesize 33 arri_aces.cube
You could convert this LUT into an ALF2 look file, and load it into an ALEXA SXT