They expand to 24" comferetable in the standar line.
Their pre styled wigs don'r expand without modifing the hair line.
Arda has a shade called light grey that would work for her.
For a base wig to do her undo I recommend the Eowyn or Ferrari and one pack of wefts.
I to have to make updo's from scratch with my 23.75" circumference and 17" long head, But I've been only using Arda the past 3 years now as their wigs fit.