Outboard motor or not? -- that makes a difference in the width aft as well as transom rake.
If not and you'll be rowing her sometimes, then the aft section should be narrower. Personally for smaller sailboats I've always liked the option of using a small outboard on an adjustable bracket on the transom, particularly when boating with kids.
I really like MMD's "designed from the inside out" description!
"The enemies of reason have a certain blind look."
Doctor Jacquin to Lieutenant D'Hubert, in Ridley Scott's first major film _The Duellists_.