Where to find a legible bathroom scale that Mother can slowly step on?

97 year old Mom moves slowly, too slowly to please the digital scale we have and so we get an Error message on the display. Bought a standard dial face scale, but it's too hard for me to read. (I'm 73 and getting my bifocals to work while looking down, etc.. . . .) Read reviews of standard scales and problems with consistent weights seem to abound. Since we want to track actual weight fluctuations, accurate weights are important. We are watching for weight gain (water retention due to congestive heart failure) and weight loss (insufficient food intake). We record what she eats (not always quantities) and monitor her ankles for swelling (she wears support knee highs), but would like the backup system a good scale would provide. Has anyone discovered a "patient scale?"