The Flex-hone is not for material removal. It's for surface preparation as is the brush posted earlier.
When the Flex-Hone is used properly measuring any bore enlargement requires tools I'm certain you don't possess. When used improperly it will take hours and hours to remove any appreciable material.
Even using the 2 stone set up pictured above I can remove half-tenths when sizing a bore. And can measure them too.
To the OP and others. My apologies for the explanations. But when charlatans offer bad advice I feel compelled to keep it from being considered good advice. Just because it makes noise doesn't mean it's right.
you don't see luggage racks on a hearse..........act accordingly