I checked, the wheel is about .050" wide and the hand insert about .070" wide. I use replaceble X-acto knife type gouge (and veiner) inserts I buy at the University bookstore.
Joel Schafer has a whole chapter on Mullered Borders in his book, The Final Touch (highly recommended!).

Last edited by SDH-MT; 01/12/18 06:27 PM. Reason: edit