I'm working on Butterick 5277 View C with the collar for my teenaged daughter.
I've made 2 muslins so far--the first was just way too big for me to see what needed to be adjusted, so I did another 2 sizes smaller. Weird since I did actually measure her first! Anyway, it looks like I need to add a small dart at the bust and adjust the armscye in the back. Not too bad, but I am ready to get into the fashion fabric!
Here's the muslin with the bust dart pinned: