I' was thinking of some how splitting off one of the wires to the a/d/s/ amp so that one of the outputs ran 2 sets going to the a/d/s amp and run one of the sets that would be my 3rd channel to the sub output.
The Autotek would get its own output so here is a little chart to explain what i mean...
Channel 1/2 would be bridged for 88w Channel 3/4 same deal and Channel 5/5 same...
1/2 & 3/4 would be left and right comp and 5/6 would run a small dayton 8" woofer in a sealed box.

Let me know what thoughts you have.