For this job, we only had a 4 conductor going outside, so we used two for the cabana speakers (wired in parallel for 4 ohm total) and two for the 4 yard speakers (wired in series/parallel for 8 ohm total).
The Cdi series allows "input Y" to combine the input for mono operation off of both channels. You can also select 70v on one channel and 8 ohm on the other simultaneously.
I use this for the interface for low level unbalance (ZP90) to high level balanced:
[Link: parts-express.com].