I do both day and night flushes.
I prefer daytime because I don't feel sick. The night ones are horrible.
In fact I'm doing one right now. Nothing expelled yet, took the oo/gfj just a few hours ago, but I am already feeling so much better. Not sure if that is directly attributable to the flush or the effect of finally snatching myself a restful day.
Hope yours goes well too.
Wishing you health, love, happiness.
Anandi