When I print d/s banners, I load the material and then mark on the heater with a grease pencil the edge of the material. When I push the button, it rolls out 1.25". I'll mark that edge, too. After it prints that side, don't cut it off the roll. Just release the takeup reel, raise the pinchers and roll it back up on the roll. It wouldn't matter if you could feed it backwards because you still have to take the material off and flip the roll over to print the other side. I like to let the material sit for an hour or so before printing the other side. Then load it back up and make sure the edges are on the marks I made the first time. Then hit the button and it rolls out the 1.25" again. The material should be on the second set of marks you made.
Another thing I've noticed it that when I tell ColorBurst to center the media, it's actually off by about 3/8" or so. I've learned that if I tell it to scoot over 2", it scoots 2.375". So, when I flip it over, I measure how far from the edge the print starts. Then I'll then tell it to scoot over 3/8" *less* than where I want it to start. Hope that helps.
I can't see where a "feed backward" option would help.