The Internet to the rescue! Since I spent a lot of time looking and reviewing, I have decided to make an entry here for my own reference. Perhaps others will also benefit. The picture molding is also referred to as picture rails, which is sometimes called Ogee or OG molding. What I have called clips are called picture hooks, picture molding hooks, picture rail hooks, and S-hooks. The rails and hooks were the preferred solution to decorating plaster and lath walls in the 1880's through the 1920's and into the 1930's. Yes, the house I now live in was probably built in the latter part of that time period.
In the realm of "how to" sites, the following are arranged from best to good:
- Picture Hang Solutions in North Carolina give the best instructions for picture rail hooks that I have found (scroll down to the bottom of the page for the instructions). The picture hanging hardware business is a spin off of their fine art gallery business. They recommend using stainless steel twisted cable instead of monofilament (fishing line), which stretches over time.
- Picture hanging instructions using picture rails shown in photos by The Swan Company featuring the backsides of frames so you can see how to attach cord or wire using various hardware. They also have an extensive photo gallery of ideas showing how their customers hung pictures.
- Martha Stewart on arranging pictures including the use of picture rails. She also shows an interesting way to hang multiple small pictures using a picture rail.
- Specialty Techniques for Historic Homes is a good place to "ask the expert," so I include it as a place to ask when all else fails. Here are a few existing Q&A's on picture rails: Picture rail molding with cornices, Using ribbons to hang pictures, Picture rail in 1920s homes, and Picture rail for curved walls.
- In Ask MetaFilter, the question was "How do I use picture rails?" This was the first such site I found and had good links. Here I found picture hooks exactly like the ones I have. For more discussion, here is an Ask MetaFilter search on picture rails.
- Historic Style has a period photo of pictures hung from picture rails and gives some historic information.
- Wide Brass Picture Rail Hooks - 2 for $1.00. One and 5/8-inch long x 11/16-inch wide x 1/32-inch thick, which is the size I have. Scroll down to the bottom of the page for specifications and very detailed instructions for hanging pictures. [from Picture Hang Solutions in Hillsborough, NC]
- 1/2 inch Simple Rail Hooks - 10 for $2.50. See also their selection. My picture hooks from college are 11/16 inch wide. [from Rejuvenation in Portland, Oregon and Seattle, Washington]
- Moore Push Pin has zinc molding hooks with two holes in them so one might use a nail to reinforce the strength of the hook (scroll down about three-fourths of the way to see the item). I don't like that they are made of zinc, but the holes are intriguing. They come 3 on a card for $1.97 and are suitable for weight up to 15 pounds. I am keeping this item as it referenced the weight that can be supported (with nail holes!). [from Office1000.com in Oil City, PA]
- Secure brass-plated picture hooks - 2 for $1.50. These also have the holes for nails. They are one and 3/4 inch long by 1/2 inch wide x 1/32-inch thick. They also come in a nickel-plated version of the same size. The secure picture hooks are recommended in areas where there are earthquakes. [from Picture Hang Solutions in Hillsborough, NC]
- Molding hook by Hillman Fastner Corp. - 10 for $22.90; only sold in sets of 10. I include this link because many of the hardware stores I visited had other hooks by Hillman, but not this one. This hook has one nail hole in it. By the way, Hector's Hardware Store [Williamsville, NY] has the same item that must be purchased in sets of 10 for $19.90. Neither Do-It-Best [Fort Wayne, Indiana] nor Hector's give any additional information about the size of the hook.
- Victorian Picture Molding Hook - 1 for $6.72. It is 1.5-inch high x 1.75-inch wide, solid brass. I include this one because it is beautiful and vintage. [from Paxton Antique Cabinet & Lamp Hardware, LTD in Maryland]
- Antique Picture Molding Hook - 1 for $2.99; solid brass. One and 3/8-inch high x 1-3/8 inch wide by 1-3/8-inch deep. [from Antique Hardware & Home in South Dakota]
- Jane Austin Collection - they seem to be selling the cord that hangs the pictures on the picture molding hook. While other sources recommend hanging pictures using at least two hooks, this page shows a way to hang a picture using only one hook. I include it for its history. [from The Swan Company in Orland, CA]
- Picture Molding Hook in choice of 8 finishes - 1 for $.80; 1.75-inch tall x .5-inch wide x .04-inch thick. [from Golden's Antique Supply in Woodstock, GA]
- House of Antique Hardware's (Portland, Oregon) selection of picture molding hooks - prices range from $.59 to $2.99 each. House of Antique Hardware also has the hooks that look like mine (brass is the same size as mine) in plain styles in steel with 8 finishes ($.79 to $1.29; 1.75 inch tall by 1.5 inch wide by .04 inch thick) and in solid brass in 8 finishes ($1.99 to $2.09; 1.75 inch tall by 11/16 wide by .05 inch thick). They also offer a selection of picture hanging cord.
- Various Victorian molding hooks - prices range from $1.50 to $8.95 with cord in 4 colors ($1.30) and Victorian tassels ($19.00). [from Crown City Hardware in Pasadena, CA]