I go the other way when sealing my buckings.
Most use PTFE/Dental floss over the bucking.
I use the barrel instead as it lets me have more control over what tape is where, and how wide that sealing point is.
I use a ring of tape (selotape or film type, not insulation tape, or plumbers ptfe) to go between the hop window and the lock points. I'll put tape on something flat, Then put another layer over the top of that Cut the width (2mm) through both layers, Cut one end and carefully lift one layer of tape off the other so I have a clean tab. I'll then take the barrel put it on the flat surface, and rotate the barrel to lift and wind the tape onto the barrel. Make sure the tape is perfectly flat, free of kinks, air bubbles ect then put 1 cut with a craft knife dead centre in the bottom groove on the barrel.
Slide on the bucking make sure it is perfect and use a pen to mark the feed lips at top dead centre. Slide the hop over the bucking but don't twist it on, You will have to use a forwards/backwards walk on method with a good amount of lube. Then check the barrel, hop and bucking are all running true (using the mark on the lips to tell you if the bucking is twisted). Fix the hop to the barrel, then degrease the nub with alcohol on a cotton bud.
If it's done right first time then it should be good for the life of the bucking. The tape isn't going to do anything under the bucking, when you come to remove it all the glue might leave a residue that''ll need to be cleaned with something like acetone or alcohol. You also won't have a hop unit that looks like the apprentice plumber has fixed it.