I saw your email yesterday but didn't have a chance to respond from work. Since you're still looking for advice, I'll throw my analysis in there.
Merely changing your plot from 10 to 20 feet cause all of the Philly stations you asked about to go to LOS signal paths. Since I have the advantage of your exact address, I can also see your surroundings and the signal path across the pond.
http://www.tvfool.com/?option=com_wr...5b9419d8d73bc0
Because you specifically limited your "must-have" stations to the majors from Philly, aiming antennas in any other direction is not part of that requirement. There are plenty of other channels in the area, but it's up to you if you choose to limit your effort to the named stations.
A small, all-channel antenna mounted on the northeast gable of your home, aimed at Philly, would suffice. No amp is needed, the signals are strong, unless you have substantial distribution requirements.
Because WPVI transmits at quadruple the power listed in the TVFool database (they've applied to double it yet again), their blowtorch signal is readily received by smaller antennas. Based on my extensive experience with it, I would have no hesitation in recommending our ClearStream 2V for this particular application even though the C2V, on paper, isn't a perfect fit.