I don’t think I saw anyone else respond to this question. Personally, I would agree that it’s a decent substitution for a reverse flye, since they both challenge the fully-shortened position of the rear delt.
Something I’ve been really liking for real delts is a cable reverse flye where:
- You stand facing the cable, side-on to the stack. This way, the cable is pulling your arm across your body, rather than forward
- You internally rotate the shoulder and pronate, so your palm is facing away from you and the cable stack
- The cable is anchored at around shoulder height so you’re pulling horizontally
That and rear delt swings light me up