I've heard a rule that you should try to see whether you can tell who is speaking if you drop all the attributives.
I've tried it. The problem is that I can indeed always tell who is speaking, but whether that has anything to do with voice is another matter. If Jane wants A, and Jill wants B, then obviously whoever's arguing for A is Jane, and B is Jill.
Sometimes on revision I have concluded that a character wouldn't have phrased something like that, but character comes across more in whether they are verbose or reticent, and what they talk of, that in their voices, either word choice or sentence structure. . . sometimes I juggle some words to make class clear, but