My suggestion to XJT (for what's worth, not much) would be to do what you have to do to make the deal happen (within reason). Once on board, you can tighten things up with the ASA group quickly and then work on the SKW group.

With the NMB rule change, and certain other issues at SKW, alpa is much more likely going forward. Even without a union, the two groups could agree on many things. While INC would technically not have to honor an agreement made by non-union SKW with ASA/XJT, it would ludicrous for them to not do so...that would pretty much guarantee a SKW union.

There are some very senior SKW CA's (mostly in the west) who are very happy with what they have, and pretty vocal about not rocking the boat. But the other 70% of us are a lot more pragmatic and would welcome a reasonable integration.