i can tell you it didn't work for us. My Rotty passed, and she was very laid back, we also have a JRT..they were raised together, both rescues.
When my rotty passed away, due to surgery complications on her knee. i waited 6 months and got another rescue, a puppy, JRT/Beagle mix. what a mistake that was. She is such a witch to him. he is now 10 and wishes he was an only child. She is 3 now.and he is scared of her..she is bossy and acts like the Alpha when he should be.
i thought we both needed a buddy.
i am retired so i am home alot.so leaving them is not an issue. Gizmo is old and he really didn't need this . chula is so good, she was a good puppy, and very loving, but she does not let gizmo do anything.
maybe if i had rescued an older dog,calmer..if would of been better for both of them.