I use to make mine on a router table... they were 5/16" x 1/2" x 1/16". What worked out best for me was to make them so that the cross appeared on the end grain, meaning you were always routing long grain and cutting them to thickness was a crosscut operation. Think of it as an extrusion.
It also helps to make them with a sacrificial piece glued on to use as a handle during routing... super glue works well. I also did not cut the profile the full length, thus leaving something to guide it along a fence. Helps to be able to turn the router off midway treating it as you would a stop cut or dado.
Hope this helps.
Watch your fingers.