From Tim Price's blog
STUFF TO SHED
Kinda nice too. Enjoy.
--over C7 use C Maj triad - C, E, G- and Bb Aug triad -Bb, D, F#- for a sound that is whole-toneish...
--over C7 use F# Maj triad -F#, Bb, C#- and E Aug triad -E, G#, C- for an altered/tritone sound.
--over C7, (normal dominant or altered), use Db- triad and D Aug triad
--over Dmin7b5 use Bb Maj triad and Ab Aug triad
--over CminMaj7 use F Maj triad and Eb Aug triad.