I still use the Carlson Wagonlit ITN fare tool, through FT. I have not (yet) registered for the KVS tool.

As indicated elsewhere, I enter an overseas segment, connecting with a domestic segment. Then, the "I" bucket fare does show up. For example, I was entering YYZ -Beijing. Some of the YYZ-YVR flights displayed were of the previous night, to the YVR-Beijing flight. In this way, for Wednesday, I found out that there was no "I" availability on AC 1163, but there was I9 availability on AC 151 (before we took 3 of the upgrades, yesterday).

However, I could not force ITN to show me "I" availability on AC 124 between YYC and YOW (I did find the availability on the connecting AC 214 from YVR to YYC) - on July 20 (I am coming back then), or July 27 (my wife/daughter are coming back then) - but I bought the tickets anyways because - those flights on Wednesdays had the cheapest tango plus fares of any individual flights/flight combinations on those 2 days, and ITN was showing J9C9 availability, so I guessed that the "I" availability would be high.

The question is whether one can estimate the "I" availability based on J,C, and (perhaps) various economy cabin fare bucket availabilities?