Although this is counter-intuitive you would actually be better off with two 8 ohm bins running off EACH channel in stereo mode with a 4 ohm load on each channel than two 8 ohm bins daisy chained off the bridge channel effectively putting each channel under a 2 ohm load ???
Would the extra cone area of option one produce more volume, or the 2 ohm power of option 2 ???
The more I learn the more questions I have !!!