When I started Opicapone I was given the same advice as Supa i.e. take it at bedtime but an hour apart from any Levodopa. I take a half Sinemet CR at night so I'm currently taking the Opicapone/Ongentys about an hour before bed and the sinemet as I put the lights out.
Overall I'm still loving it. I wear off very infrequently now. Side effects are mild if any. I may be getting my dystonic foot a little more often than before. My appetite may have increased and my bowels may have slowed a little.