Once you cross this line both your continuous and peak power will start to drop per channel if all channels require the max all at the same time.
It's that last sentence that really sums it all up. And this is where we need the guidance as you are using the 4 channels of the amp to drive 2 speakers.
Now if you were bi-amping this were one amp channel was being used to drive the large woofer set, and the second channel was getting used to drive the smaller mids and tweeters, you likely would be saying the power pull on the channel driving the woofers would be much higher than that of the mids/tweeters as those drivers have a much bigger coil and far more displacement moving a larger mass cone.
Can the same be said for the rear set of drivers on the LFR? So in essence, the ADA1500 will likely be getting a dynamic output closer to 2000w than the 1050w (350x3) if you were driving a full range speaker on each channel instead of the DSP driven rear LFR channel.
Hypothetically of corse .. not trying to back you into a corner and committing to something that has too many variables to quantify exactly.
I am looking at it from the side that the ADA1000 in reality gives you an upper limit of 750w.
