I think two Hydras in series would be overkill Sam. I sold a Hydra to a customer that was in the same dilemma as you, and his final solution was similar to what you mention--he got rid of the PS Audio PP600 he was using, sold some of his King Cobras, and ended up with a configuration of Hydra into wall, King Cobra v2 on his digital into Hydra, Viper v2 on his phono preamp into Hydra, and then stock power cords on everything else. He found that additional KC, Vipers, or Sidewinders after introducing the Hydra made small improvements on linestage, power amps, tuners etc..., but not enough in his opinion to justify the expense. The fact that digital still needs a quality cord even with Hydra is not surprising, but the phono pre results I did find interesting. Perhaps it's because of the low voltages and sensitive circuitry of a phono stage? Anyway, that was one customer's results, YMMV.....
Shunyata Hydra Info Available
Website now has product info posted for "hydra" http://www.powersnakes.com/hydra.htm Unit has six outlets and retails for @$2000. Hydra contains enhanced "stardust" technology found in KC2, viper, black mamba. Now the question is if you have 4 KC2s in your system your cost new is over $8000. If you buy hydra and 4 sidewinders you have spent @$3000. Is it possible that hydra/sidewinder sounds the same or better than KC2 by itself? Comments from members please.