Before I cut the "backs" off of mine 6 years ago, I did the same thing, only I used the small cut off discs that come with the Dremel tool and I went from the back and let the disc grind through the lower portion of the rib. It worked perfectly and looked nice. However, once I was done I wasn't sure what the point was and had spent so much time doing it. Then I took the same cut off disc and cut the back off the other one. Fortunately for me, I liked the look of the open one better and then cut the ribs out of the other side. Then I took the grinding stone attachment and cleand up the surface. They ultimately came out really nice and I am happy with them...