This is the plan to help the wife on the bigger climbs here. In fact, she has been running a 28 (Salsa) in place of the 30 for a while with no issues. The two new TA rings arrive soon.
I tried to find a 38, but no joy. Though the capacity exceeds Campa's recommendation, I think that will be OK. My only real concern is the dynamic of the 39 to 26 shift - do it with care, I suspect.