I use Jason's craw+anise & do pretty good on it.I add it during packaging & it scents them & lets me move the baits around to get them places neatly.When i was 16-18 years old there use to be this craw oil scent id get that had real crawfish sediment in the bottom along with a really strong craw scent.I haven't seen it in forever,it use to be sold local. Your ? about time of day/year I haven't noticed a scent shining more during certain times.I do believe that scent can't hurt,i feel that if anything it will help & give the fish something to target in on kinda like a shark does to a blood trail. I feel if there's a scent trail & you're around fish,they will pick up on it or they can target the bait quicker.