Hi. I'm relatively new to the forum and not sure if outside links are permitted but here's an article with a lot of links to finding the right sling with comparison charts and such: https://www.examiner.com/x-23788-Mi...d3-Finding-the-baby-sling-thats-right-for-you and here's a link to patterns if you want to make your own (lots of types) : https://www.examiner.com/x-23788-Mi...1d5-Free-patterns-to-make-your-own-baby-sling
If you get a wrap type it will fit any size, or you may find it's worth it to get you each one that works for you. People have very different preferences even if it does fit both. My personal favorite was the Kangaroo Korner fleece pouch (no affiliation), because I'm very little and have chronic neck pain (and have big babies!) and it was the only type that didn't end up hurting my neck and shoulders. It was also so simple to use-- you just slip it over your neck and one arm and put the baby in whichever way you want him to be positioned. But I think every one of my friends had a different favorite.
Good luck! HTH!
~Alicia