Pratt

I'd endorse Champlaincycler's idea. Alternatively, a piece of 3/4" ply, attractively chamfered on its edges and large enough to span a pair of studs, painted to match the wall, then mount the item to that.

chanpo

I was in process of finally installing this on my wall, only to find no hardware for my drywall. I used the toggle anchors recommended by Chuck M. Thanks a million! Installed yesterday after a trip to Lowe’s. Came out great and feels solid.

Camilo

I'd make a nice-looking board out of veneer plywood or solid wood and finish to your liking, either painted, wall-matching or a nice wood finish. Could do the same with a piece of aluminum or a couple of solid wooden or plywood slats or aluminum bars, one at the top and another at the bottom. Either way, I'd make the size so it would span the studs, but when I mounted the rack on it, it would make an even backing border all around the rack, or in the case of bars, evenly spaced side to side. Nice screws too. (poor rendition, but hopefully conveys an idea.