I would try to steer clear of any wahs that are going to color the sound of the guitar.Since you play a lot of bluesy stuff, you don't want to push your tones too far over the edge. Go to a guitar store and play as many different models that you want. Try to find a guitar with similar pickups (or take your own...) and try to find an amp that is similar to yours so that you can closely emulate how it would sound in your effects chain. Set the amp that you are going to play through to a clean setting so you can tell if the wah will color the sound. Then start playing wahs. Once you find one that you think you would like... start playing it with everything set-up closly to how your set-up at home is. I would recommend checking out the Dunlop Jimi Hendrix wah. It doesn't have the adjustability that you want... but it gets the job done.... JIMI style.