I think XPOL cross polarized antenna will do similiar job.With regards to the antenna setup the only setup I've seen is the 2 separate antennas, setup at a 90° angle, and yes its designed to get the most out of the devices capabilities if the signal isn't full.
Anyway, your sticky thread need updata with LTE related stuff (voice calls 3G handover, antenna installation, etc). Rememnber you wrote something?