Specialtech for the incredible customer service and price matching, plus they'll order you pretty much anything you want. Their 1-3 day supersaver shipping option has always been next day for me too.

As general advice I wouldnt bother with the PHN, G11 or Hydrx, they're a total waste of time. Stick with Pure distilled water and a silver killcoil. If the only metals you have in your loop are copper/brass/nickel then you won't have any need for corrosion inhibitors anyway. Pure distilled is better than any of the specially formulated (snake oil) coolants out there.

Smartcoils are the same as any other anti-kink coil out there. You shouldn't really need them unless you're planning on making your tubing into a knot. Just plan your loop properly so you have short, straight runs and as few turns as possible. This will stand you better in useage than just using kink coils and tight bends in tubing.