I'm all about getting as many channels as I can lol, independent of video quality. I experimented a lot with combining different antennas, and with multiple (even "exotic" one-off) amplifiers with my roof setup. I had DUAL 4228 vertically stacked, I had 4228 stacked with a medium-sized Winegard Yagi. Added benefits of stacking at my location were negligible, just added way too much weight to the mast for my comfort level. I tried multiple amps - 7777, 7778, Winegard AP-something, some special amp with very low noise floor from the States. At the end of the day, I just went back to 4228 and 7777 at both, my and my parents' roof setups.
Note that I run a single TV with no splitters to minimize signal loss between antenna and the TV (although I have an active splitter installed between theater room and upstairs, just bypassed it).
I never had any problems receiving CIII, CJMT and CFMT (41-1, 40-1 and 47-1). My problematic channels are generally 49.x (sometimes when I am lazy to rotate antenna a bit), 51.x and 56.x. I'm surprised you are getting flaky CIII, being 100kW transmitter power, but we don't really know their radiating power. CJMT, CFMT and CITY are definitely weaker stations, so I'm not surprised that you can't get them in Buffalo.
CITY-TV got flaky a little lately, I don't know what's going on with them. Again, having a rotor, all I have to do is rotate 10-20 degrees towards Toronto to receive it on main lobe rather than on side lobe to get it rock solid.
Auto-programming new Sony TV at my 'default/lazy' antenna location yielded 54 channels - that includes 12 56.x channels, which don't want to work right now. For some reason, 67.x never appeared on the scan (that's 4 more channels that I can get). I'll play with the rotor on the weekend to see if I can get 56.x back.