Yeah. It does sound like a name for a jazz band. As for the chords, a diminished chord doesn't have a 6th. Names like diminished, major, and minor are given to the configuration of the triad (1, 3, 5). Everything else is an extension. A diminished 7th chord is 1, b3, b5, bb7 (or 6, enharmonically). A diminished 7th chord doesn't exist natural in a major/minor scale, instead it's a m7b5 chord, like Bm7b5 in C major. A m7b5 is 1, b3, b5, b7 (B, D, F, A).

andy-

Just think of the root notes as a scale and see what scale it fits into. Usually you just have to look at the first chord you played, and figure out where the rest of the progression fits.