Yeah, RZ is good with frags.
But just to let you know, I use those discs in my frag tank and it isnt hard to remove a zoa mat from the disk. Just use a razor blade along the top of the disc angled somewhat down so that you minimize cutting the mat. Easy to do...
Oh, and one more thing. You dont really have to remove them, because once they start growing out you wont see that disc. But if you decide to take them off the disc I would advise gluing them to the rock in your tank so they dont get blown around in the current and lost, or knocked over by some crazy little hermit...