Clark Girls

So, as you all may know, I am planning on adding another pup to the fam! Mavy would love a little sister. But I am torn about whether to get a cavalier kind charles spaniel, which are known to be super friendly and get along really well with other dog, or a West Highland Terrier (aka Westie). Cavs have some potential health issues, but better personalities, while Westies are more likely to be yippy and whatnot. I need help! If I get a cav it will be black & tan or the ruby color shown above. Westies only come in white. And I want to name her Petunia! Other name suggestions are welcome.