Holding coins for macro photography

I want to get into macro photography a bit, and my plan to start is to shoot a bunch of foreign coins I've had for years.

I have camera, lens, lighting and macro lens. I have a macro rail also. What I don't seem to have is a good way to get the camera parallel to a coin. I'm using a Gitzo tripod with a RRS ballhead and RRS macro rail. It's not conducive to pointing the camera straight down.

I'm looking for ideas or products to hold coins at a reasonable angle, without sliding or rolling away.

My first idea is to go out and get an old music stand, tilt it to 45 degrees or so, and adjust height as needed. I then point the camera at it and get the camera carefully lined up to be parallel.

Holding the coins in place on an angle is a problem. I've got a cellphone holder that is designed to mount to the dashboard of a car. It's got a non-slip surface, and I'm thinking that might just hold coins in place while I photograph them.

Ideas?

--
Craig
http://www.cjcphoto.net