A flag on the pier ? Good luck with that. For a chance at catching yellowtails a chum block helps but isn't needed. Small bottom baits fished on the reef will catch ytails at certain times of the year. I have seldom seen them thick enough to target and catch any number of them at one time. If you catch 2 or 3 keepers you are doing well. Anglins gets a few at sunrise during the summer and spring. Cleaner water seems to move them in. I would use a 12 - 20 lb mono rig no leader small hook and lots of patience.
Dreaming the dream that one day I can be as good as some of the boatless pros and catch some 12 inch mangrove snapper.