Recommend you make sure what sort of 5-pin alignment method is used for the Project arm.
I believe most 5-pin DINs have an alignment pin to facilitate mating orientation. (My Moerch arm on one table does...). However, my Origin Live Enterprise MK5 arm uses a larger recess for alignment (not a pin groove) and the Origin Live Silver Hybrid 2 DIN-RCA cable that was included has the mating extrusion ("bumpout"). When I replaced the OL cable with my Luminous Audio Technology Silver Reference, I went ahead and filed down its mating pin to allow insertion, as the Origin Live connection has no pin groove. May just be an OL thing...