[orange 71 chevy]

hi i bought a new bead roller from east wood tools so i can make the flange on back window of 71 chevy truck but the flange tools are too small does any one make a 3/8 flange or is 1/4 inch the common size.i 'm afraid to use it because the bends are to sharp and i'm measuring a 3/8 bend from back wall to flange bend.does any have an answer.