Just a thought. If the new 8 ohm system is all wired back to the amp, would it be possible to use a speaker wire feed from the 70v amp location about 200 feet away to the home run speaker wires in the building that houses the Pheonix amp, then wire in parralel from that location?
I have wiring in that building that feed 8 pairs of speakers.
This way, I can locate the crown amp in the same building as the source equipment, feed a line from the amp 200 feet to the building that I have the wiring for the 8 pairs at. Also, I have a cat5e feed from building to building.
Does that make sense?