So good!

I tried to figure out Headhunterz's saw layering a couple of months ago: https://soundcloud.com/getyoursnackon/nothing-can-hold-us-down-supersaws/s-0uRSu To me, most of his sound comes from his writing/MIDI. The actual patches are pretty standard-fare Sylenth supersaws, with a pitch mod on the attack. It's easy to get 95% the way there with basic processing, but there's some texture about his that I can't really get with Sylenth alone... I recall hearing that he uses a Virus TI for these sounds, so perhaps that has something to do with it.

The most obvious thing to do is add 7ths and higher extensions (# or b 9ths/11ths/13ths) to a regular diatonic progression and see if it works. You can also replace dom7 chords with another dom7 built on a root a tritone away - tritone substitutions create chromatic movement in the bass and that's a pretty common thing to do in jazz. The "level" of jazziness ultimately depends on how many chromatic passing tones and non-diatonic spice are added.

I find pitching samples up a few octaves helps make their tone a little more obvious. You can then throw in a synth with a note playing a scale degree of your song to tune your samples to. Usually I'll stick to the tonic, 4th or the 5th as those intervals work with most chord changes.

Hijacking this thread real quick to ask what the best stereo imagers are. I'm getting bored with iZotope's.

The ones I use frequently: S1 shuffler, Sound Toys Microshift, and Sonnox Stereo Tools. I just heard about Dr MS and Brainworx XL from a friend today, and they seem really interesting. Dr MS apparently lets you control the width of the center and side channels, and can create some cool weird 3D stereo effects.