OK, fair 'enough. I do agree that RF14 will improve reception significantly, with the proposition, it will work... but I still think it's not the best channel number, for the sole purpose that if they want to increase power in the near future, they won't be able to do so without creating interference.
Really, the coverage with 160 kW from the top of the tower on channel 14 will be miles better than they had with 50 kW from the bottom of the tower on channel 6.
When I check on wiki, many US transmitters on UHF band are somewhere between 200 kW and 1 000 kW, while the majority of Canadian digital transmitters are low and medium power since the transition. For example, Buffalo ABC (358 kW), NBC (480 kW), CBS (790 kW), Fox (1000 kW), CW (1000 kW), while Toronto CBC (107 kW), Global (100 kW), Citytv (21 KW), Omni (22 kW)... Canadian networks will either want to increase power to allow mobile/handlet services (and more revenues), or keep them low power just so they can keep their simsub rights.
The regulatory and industry environment is different here. The American stations are not owned by BDUs, and moreover, the FCC has a "use-it-or-lose-it policy with respect to allotted powers. In Canada, this only applies (so far) to FM stations, which is why over the past year you've started to see some FM stations increase their power.
You quote some high power Buffalo area stations, but you don't mention that, locally, WWTI ABC Watertown is 25 kW, the PBS stations are 40 (WNPI), 55(WCFE), and 60(WPBS) kW.
I'm shooting in the dark here (assuming everything is at Camp Fortune, which isn't true), but Global could share an antenna with an existing co-adjacent number, like 16 or 18 with CITY-DT-3,
16 is allotted to Watertown, and would require FCC agreement.
18, while currently used by an unprotected LP station from South Colton, is actually allotted in the international agreement as a full-power (30kW) station at South Colton.
CITY is at Herberts Corners. Even if Global moved there, it could not use more than 51kW adjacent to a 5.1 kW station according to the rules in BPR-10.
23 is WNPI South Colton! In any case, you can't simultaneously be adjacent 22 at Herberts Corners and 24 at Camp Fortune.
28 with Omni.1, 29 or 31 with CIVO,
These might work, but I'm not sure how high you could go in power. They are currently low power allotments in Cornwall.
This would have been a good choice, but CBC grabbed it first! (And they own the tower)
41 with CHOT and/or CITS,
again, you can't straddle CF and HC that way.
44 with CHRO, or anything beyond that seems to be empty for now...
Some of these other higher number channels are allotted to adjoining areas, like Arnprior and Smiths Falls. There is also a high power open allotment on 50 at Herberts Corners.
The bottom line is that there is a fear that 31 and up will be abandoned, which makes any high power available spot below 31 much more feasible in the long term. 14 is probably the best bet, given that it was already used here during the pre-transition phase. The only other possiblity would be 19, but then it would have to be very low power (to protect SRC Montreal) and at Herberts Corners (adjacent to OMNI2 on 20). And frankly, that would prevent more people in the Ottawa area from getting WNYF on 18 than being on 14 would interfere with WPTZ on 14.
Personally, I think the cheapest bet would have been to reuse the existing channel 9 antenna (if Camp Fortune Tower's owner CBC would allow for it) at 20 or 30 kW, but that would still not be good enough for mobile-ATSC use.