Tried with a Jackly 6032A (32-head screwdriver set) - where I had T4, T5, T6, T8, T10, T12, T15, and many more..... none worked.. God knows what spec they used. None is exact size; either big or small..
Photo: https://www.dropbox.com/s/qeg57g4p4hxu0x8/P_20170807_200748.jpg?dl=0
So, now I will...