Montblanc as a gift sizing question

[Bluside]

Hello all.

I want to buy my SO a nice Montblanc pen as a congratulations present for getting her first book published.

First let me say I don't know anything about Montblanc pens. I have just been doing some research lately. I'm leaning towards a ballpoint Meisterstück.

I believe the 149 will be too big. Can anyone recommend the proper size to get for a lady? She is tall and thin if that matters.