You can always run a single 12 now and then when it's time to upgrade again add a second run to biwire.
A valid point, and a misunderstanding on my part.
You could try buying both from a place that allows returns, or if fatwyre.com (I think that's the right address) has them you could rent them. Listen to one combo for one week, then the other for a week.
You could also speak to John at Satellite to the Stars, who's an AP dealer and a straight shooter.