I'm trying to find some flatwound strings for my 5-string warwick thumb. The issue is that I got a set of flats and the low B was at a .130 gauge, which was too big to fit into the bridge. I can't seem to find a brand of flats with a low B anything below a .130. I think it would fit if I could find a .120 or maybe a .125. Do these exist, does anyone know where to find strings like these?