I bought five cotton handkerchiefs from T.M.Lewin. Â They're all too big to be used for breast pockets (20.5" square). Assuming a 38, perhaps 40, size jacket what size kerchief should I buy? Â I've specified the jacket size in case it's related to breast pocket size. Before anyone castigates me for buying cotton, let me work on the size before the material. TIA.