I'm fairly sure that you cannot change the bokeh shape of the Matso DoF. You That setting is for a different DoF. You should probably use MartyMcFly's newest DoF, or the one already in the reshade package, but his newer on here is much better: reshade.me/forum/shader-presentation/4393-quint#28351
But yea, only the DoF settings labeled Matso with impact Matso DoF. Someone please correct me if I'm wrong.