My wife had her sit bone width measured and tried two different WSD bike seat and did not like either one of them.
So I put on a Specialized mens seat that was about 10mm smaller width than the women's seat and she likes it and rides 60,70 and some 80 mi. rides. Your wife will likely have to try a few bike saddles until she finds one she likes.
Bigger is not all ways better when it comes to seat fitting.