This sounds like a good approach. If you do what you describe (large fronts, no sub, splitter on the left/right pre-amp outputs to feed each channel to one Active 20 and one LFM-2), the LFE channel will be re-directed to the fronts and will get to the subs. If you set the center to small, its low frequency data will re-direct to the fronts. Same for the surrounds. Oh, and you'll need to adjust the subs' crossovers to blend them in with the Active 20's.