Which speaker should be on top?

I have two speakers which require corner placement: Khorn and TacT W410 subwoofer. Seven foot false corners will be constructed so that the speakers will be 60 degrees apart from the sweet spot and positioned out in the room to get the best imaging. The mid and high horns will be at ear level. This means that the Khorn bass and the subwoofer boxes have to be on the top and bottom. The problem is which should be on the top and bottom? Aesthetically it doesn't matter because everything will be behind a decorative cover. Any suggestons?