We couldn't use Grace as it jars horribly with our surname, but Gracie goes quite well and I love it. I'm not a fan of nicknames as names, but I've found Gracie in the top 500 names of the 1880s and 1890s so using it as a first name isn't new and it goes really well with my DDs name. I worry that it doesn't sound serious, but it doesn't seem that different to Katie to me and she could always use her middle name.
We're not pregnant yet, so this is very early planning, but last time we had all our names worked out before starting ttc, so I thought I'd ask for opinions!