When negotiating for the 787 the company quite happily told the AIPA negotiators they were looking at a fixed cost per ASK to determine an appropriate 787 rate of pay. I also heard them state on multiple occasions that this cost would also be a factor in future aircraft replacements. It shouldn’t be too hard to extrapolate that cost from an aeroplane with 236 seats to one with 350+ and determine the pay rate.
If it ends up being a ‘common fleet flying’ concept between the 787 /777X or A330/ A350ULR then that also provides significant efficiencies to the company.
So the company may be starting at 787 rates. That’s not where they’ll finish though.
I love your confidence, however would you bet a testicle on it?