I suggest calling our supplies department at 1-800-822-2200 they will be able to assist you with the correct media.
Please check out this article on Paper Specification for recommended media.
I'm printing postcards with 300gsm cardstock. I want to print both sides and I don't mind having to feed them through once for each side, I'm using HW4 and HW4 Reloaded as settings, however on the first pass the system has bent them enough that when I flip them and run them through the manual feed again it prints 2-4 and then thinks there's no paper in the feed. I can bend the cardstock back but when I'm printing 500 cards it a bit of a hassle.
Any ideas or is there recommended Xerox cardstock that would solve this problem?