Or...what some including me have done with our .45 leather loops to hold .38's is to run a piece of rawhide or such through the loops, up one, down the other, for as many as needed then tie off. You could probably get by with something much thinner, in a light color.
Like Pony Express, my first thought was regarding the waistline. I was going to comment that I just did that at the last match with my canvas shotshell belt. It's been a little loose, so I just stuck some bandanas in a Crown Royal bag, rolled it up, and stuck it under the belt in back. Hassle, but it worked okay.