Thanks. I didn't link your previous posts to this later one. From personal experience, signal to noise and pass band frequency response are critical to reception.
Forgive me if I am repetitive in any of the suggestions, but I think we should start at the beginning again. If you have access to a spectrum analyzer, you will be looking for the most rectangular appearing signal for each station (you may not be able to see any differentiation between 12 & 13 since they come right up to each other). If you don't have access to the analyzer, you will need to use your signal quality read out from the receiver.
I'd start out with very little or no use of amplification at first, and send the signal to a one TV only with no splitters in line. If you get no reception of any of the three High Band VHF stations (WXXA, WNYT, WNYA), then I'd add the antenna mounted preamp and see what you get.
Assuming you get a signal at this point, compare the signal quality on each of the 3 HB VHF channels and rotate the antenna to the best average signal quality for all three stations. I suggest this because the refraction of the signal around terrain and reception from multiple paths will affect each of the channels differently, and can result in significant frequency response changes in the pass band for each of the three channels.
Once you are able to get a good compromise signal quality for the 3 HB VHF channels, then check out the Low Band VHF (6) and the three UHF channels to see how they come in.
Next, add the splitter to feed the additional TVs. If you need some more amplification to overcome the losses in the splitter, be careful about the amount of gain you add, since you will be adding significant amplifier noise to the signals as well. Add just enough to overcome the losses in the splitter, and maybe a little more using the signal quality indication as your guide. I've had good luck with an amplified variable gain 4 way splitter available at Radio Shack, but I do not see it in their current catalog.
Make sure any unused outputs of the splitter are terminated with a resistor plug, and make sure there are no unterminated lines going to rooms or TVs not actually connected.
Using the above process you should find a way to receive all of the local stations by compensating for the receive path and receive system components.