You really can't go by a number as to what is a healthy weight. Like people, hedgehogs come in all sizes and what is a good weight for one may be too thin or too fat for another. Go by her body shape and how she feels. Some are slim runners body shape but they shouldn't be concave at the sides and they should not have a boney feel to them.
Edited to correct: I put they should be concave. It should and now does read, they SHOULDN'T be concave.
Edited to correct: I put they should be concave. It should and now does read, they SHOULDN'T be concave.