I dunno, everything Oakleaf says there (and generally otherwise, FWIW) seems pretty reasonable to me.

I do these reverse flyes. You do have to be very careful to use your abs to stabilize your back muscles. I do them bent over, with no support. I actually do them with feet parallel, shoulder width apart, since it feels strange to me to do a symmetrical exercise with one foot forward and one back (I will put the opposite foot out to support a one-sided exercise though).

One other thing... Start with a MUCH, MUCH lighter weight than you think you should be using. I have a super-weakling upper body, but to give you an example, I can do bent over rows (also both sides simultaneously) with 60 lbs in each hand, but for the reverse flyes I'm using 12-15 lb weights in each hand -- the "girl dumbells." It's not because I'm "afraid of bulking up", it's because with heavier weights I can't maintain good form throughout the entire motion for more than a rep or two. So yeah, I'm weak... You're probably much stronger, but take that general idea to the gym...

Good luck!