Wow, I am surprised they come from the roof. It looks like you have a forest in your backyard. I wonder if the raccoon lives in your attic. That is not normal for a raccoon to appear on your roof every night and come down the gutter. They can easily climb a fence or just walk around the house. Have you heard any noises in the attic? Many people have coons in the attic. If you find a lot of their phecies on the roof, there is a good chance its home is your attic. They don't sh*t where they live (inside your attic).
I 'd be putting cat food out in the backyard. They can't resist seafood flafored cat food and table scraps, but that could bring in unwanted skunks. Food on the ground, especially cat food, is advantageous in that it makes the bandits (or possum, etc.) stop and spend some time in the same position giving you the opportunity to take your time and place the pellet in their brain. I always recommend practicing with your gun at the distance and angle (like shooting downwards from an upstairs window) where you expect yourself to shoot from and where the critter might be, so there are no surprises when you squeeze that trigger. The POI is usually different when shooting up or down and 5-10yds can also make a difference. Shoot them between the eyes if you can, or between eye and ear. Do not risk a shot from the back or if they are facing away from you.
You are definitely on the right track. Lure him in and then raise that towel and let him have it. They are very aware when those flood lights come on, so either leave them on at night so they get used to them, or use exclusively a soft gun light. They may look up at you when you shine the gun light (or when you hit that switch - they have amazing hearing) at them, so stay perfectly still until they look away and go back to eating. I bet you have more than 1 raccoon that comes to help themselves to your bird feeder. Have you considered buying a "ding donger"? It makes it very easy to know when they are out there. Good luck and don't forget to post the pics!