What about a booster seat so your wife sits higher up?
Yeah higher up might fix it.... because if the seat would go higher or the b piller adjuster go lower it might fix it.
Although whenever you look at any of the possible solutions (bolster cushions, seat belt clips, even the sparco belt covers) it always comes with the caveat that any of these will basically impede the function of the pre-tensioners or airbags and could basically mean in some way you get mangled/killed in a crash.
Its quite bad that this is a thing with cars...
Mrs G put a post on some girlie group on Facebook and she had hundreds of replies from other women saying this is a problem for them too...