I have a vintage Ever Ready brush coming that I want to restore and was wanting to get a knot ordered for it but don't know what size. I was looking to make this a brush suited more for soaps as I have a good cream brush. From looking on the board it looks like most Ever Ready restores used a 20mm knot. Would this be a safe bet to go with? It has a C40 stamped on the bottom if that makes a difference.