Iam 5ft and thin and yes Iam still on the fence which size would be better for me, I carry med/large bags but dont want to look like a small girl carrying a huge bag
I am 5'8 and the PM is perfect for me! It can carry everything you need and still have room. I carry: sarah wallet, mono make up case, sunglasses, iphone everyday and it still has tons of room.
I'm 5'3 and Very slim UK size 6-8! I have the PM and it is perfect! I think I could still pull off the GM if I really wanted to because the monogram canvas on the Galliera is very soft and mushy and slouches in a beautiful way when you put your things inside it!
I think the GM would look just like you said, a little girl carrying a BIG bag!!! I would think that unless your one to carry LARGE bags (like me) you should go with the PM.
I just ordered the Mono Galleria PM I like the lighter color but Iam a stain magnet my next purchase may have to be the Palermo PM this was a hard choice