Cedar tends to split easily, and the corners of the FFs are liable to damage, so I am reinforcing the back of the FFs here with a crossgrain patch.

First I cut off half of the back of the FF tab:



Then I cut a reinforcement with the grain running the other way.



The close-fitted patch is glued with strong hide glue



The finished tab is trimmed to shape and invisible from the front of the bass.



Broken FF tabs can be repaired in a similar way.