The value of the plastic slotted stand described on my web page is that it transmits light like the main coin stand. I think I'll make a bigger slot for the bigger coins. That will be better than trying to prop them up, even though I just invented an ingenious prop.
The Ingenious Prop:Take one small piece of sheet steel (a UK penny will do, that being steel with a thin coating of copper) and two small neodymium magnets, easily and cheaply available on line. These magnets are very strong. (Don't bother trying this with fridge magnets. They are too big and too weak.)
The penny goes under the lid of my sandwich box stage. It's held in place by the two magnets on top of the lid, and conversely their attraction to the penny holds them in place. They are attracted towards each other, so the coin to be photographed, on edge, goes between the magnets.
This is mechanically
fine, completely adjustable, and the smooth magnets with their rounded corners are not likely to scratch coins. But as a background, they are too obtrusive. Also, they do have the drawback that if you let the magnets attach to each other you'll have a problem separating them again. See below a
side shot of the apparatus, and a photo taken using it. This coin is my pseudo-Thasos
tetradrachm, crystallised and with a chip out of one edge.
A bigger slot will be better ...