I think probably the idea should be as follows .... a IIm7 is frequently followed by a V7 going to the I, and then you can play the dim hw scale off the V over both chords (IIm7 and V7), and I've been doing it recently, just running the scale fast. Sounds good. This is pretty much standard practice I think. You can also play a whole tone scale off the III over both chords, I've been doing this too, sounds good ! And, I think it's a good way to start expanding your aural concept.