One of my clients daughters is in a musical. The dress was tight at the waist, and being a vintage there was not fabric to add that would not be noticeable.
But luckily it was too long. Rather than cut from the hem, I thought it best to cut from the top of the skirt. The reason - I was going to add to the bodice which meant the skirt would become too tight. By lowering at the top of the skirt, I would be able to fit it bak on without adding, In fact I had to take some off the sides. It fitted perfectly.
Happy altering
Judith