Still building a single speed. I already have some 3TTT drop bars with a 26.0 clamp. I was told by a coop employee to find a quill stem that's long enough that you can't see the front hub when looking from directly above the quill stem. He suggested 100mm in length. Also mentioned was that 25.4 clamp stems will work with 26.0 bars. Is this true? Would a 90mm stem suffice?

TIA,
Wheels