Alan, I bought aluminum J channels at the lumber yard. Very economical, comes in 8 or 12 foot pieces. Lightweight but strong. It is used as edging on 1/2 inch thick material. The ones I got had holes already in it to screw it to the wall. Would need a pair of snips to cut it to length. See diagram for how to orient the two channels. Space them so you can lift a slot glass up into the top and then down to set in the bottom channel, with the top of the glass still caught by the top channel. I like it because I can remove one piece and replace with another, or move them around as I want. Hope you can understand.
Good luck Doug in Kingman, Az.