I could not find the style and size thumbwheels I needed, so I scaled the excellent work of Workshopshed for a couple of American sizes.
These fit nuts for a 1/4" bolt thread and 5/16" bolt thread. The tool size for these nuts is 3/8" and 1/2" respectively.
Thus, the 1/4" thumbwheel is the equivalent of a 3/8" socket, and the 5/16" version is the equivalent of a 1/2" socket, if used as a tool over a thumbwheel.
Note: 6/8/15: I fine tuned the 1/4" size to be a more perfect fit.