Sand Clear: AM or PM feeding for a stalled at night horse?

For those who feed Sand Clear once a month for a week to purge sand: do you feed it AM or PM for your stalled overnight horse? I’m asking this because I’m wondering if it makes a difference if it’s fed on more of an empty stomach (AM) ? My horse grazes on hay and pasture all day but to maintain correct weight she only gets 1 or 2 small flakes in her stall at night when she comes in. She usually finishes that in about an hour or two. So by 8 am when they feed, she hasn’t technically eaten hay for about 11 hours. Maybe it makes no difference…any vets out there?

SandClear is meant to get rid of accumulated sand, so I doubt it makes a difference. But I would think in theory it would be better to do with more hay in their systems, as some studies show that hay itself can be effective at removing sand. So you’d be adding the Sand Clear when clearing out is already happening - a double whammy of sorts.