The additional 6' of height improves the Buffalo signal strength by only one tenth of a decibel, virtually no change. If the additional height overcomes a nearby obstacle it would be worth the time and effort, otherwise, don't bother.
If I were in your situation, starting from scratch, I would install an RCA ANT-751 pointed to the NNW (44° compass). I would not install an amplifier or preamp. I would pursue the Buffalo stations separately using an XG-91 and a CPA-19 preamp.
I would use separate cables from each antenna to each TV.
http://forum.tvfool.com/showthread.php?t=2882
(You already own the CM-4221 so I would suggest trying it to see if you get acceptable high-VHF reception)