At the risk of overthinking and therefore over-engineering this you might:
- observe your sister while she is turning to figure out where she puts her feet. Will Lerrums at MASW makes the turning studio platforms extend beyond the headstock and under the bed of the lathe by notching out for the feet under the headstock.
- 8" would probably twist my ankle, or worse, if I stepped off without looking. Perhaps a toe kick around the perimeter would prevent an accident and avoid having your sister end her turning career early because of injury.
Best of luck to you both and safe turning!!