The attachments are made to fit a flat suede band of the same type used for tying shoes. They're cut and ground from 16ga. brass. Since I have no drill press at the moment, I farmed out the drilling of holes and slots to Newtown Hardware House down the street. I next rubbed a small half-round riffler over the edges of the slots to round them off and hopefully keep them from cutting into the leather too badly.
After being annealed one last time, the upper section of each slot is hammered using various steel bars and rods to shift it out of plane relative to the rest of the piece.
The leather band should now pass through the slots even when the attachments are held flat against a surface.
The attachments are to be nailed down, two on either side of the wooden spine, using oversized 5/8-inch upholstery tacks. These are, unfortunately, only brass-plated steel, so they can't be polished; thus the brass belt attachments are left dull from annealing so as not to clash with the tacks' antiqued finish. The usual arrangement of rivets or nails on the front of the gorytos seems to be a lower cluster of three and two pairs above it, but there are a few examples of a single upper pair, which is fortunate, as I ran out of brass plate at this point.
One last note: Given the cross section that I picture for the wooden spine, it seems likely that the shanks of the lower attachments will have to be bent to angle upward and nailed in with great care. Since the lower attachments are to be the load-bearing ones, the angle at which they would go in if they remained perpendicular to the inward-tilting surface seems like it would make them want to yank out under pressure.
Until archaeological findings come to light, it's not impossible that gorytos belt attachments were made in a manner similar to mine. I would, however, sooner expect that if they were made of metal, they would have been cast to shape.