Mike, what you've described isn't entirely clear to me. First, although you said that you're running line level outputs from the 1080, apparently you actually mean speaker level. Then you say that you daisy chain(apparently with speaker wire)to the speakers, which you say creates some placement problems. So why are you doing that? The speaker wire to the speakers should be connected directly to the 1080 speaker terminals. Then since the 1070 has no sub out and connecting the spare set of preouts to the single sub line level input isn't advisable(see Rick Widner's link on this), run another set of speaker wires from the 1080 terminals(trim the wire ends to fit if necessary)to the sub. You won't have much in the way of bass management since the speakers will run full range and the sub has only a low pass filter(not a full crossover)to roll it off roughly above the setting on the sub.
