I am from Morocco where we use something called Sardine paste to catch sargo. It's a dough that contains sardine and flour and beach sand. it's very effective but it doesn't work in all conditions, like when there is too much wind or the waves are too big (>1.5m).
Is there something better?
Sargo are bottom feeders, and prefer crustaceans as their staple diet. The most reliable choices for bait include shrimp/prawns, mussels, squid, clams, and sea snails.
People also catch them with worms, and small pieces of fish. Where they're plentiful, they'll eat other bait that people have on hand when catching similar fish in the same water.
There's also another paste in addition to the one you mentioned. It's made from bread/flour and cheese, and the sargo seem to enjoy it.
Sources for this information:
How to Catch a Sargo
Pier Fishing
Targeting Sargo
Seafishing Marine Species
The Outdoor Lodge
Another tested bait with very good results is fresh chicken breast with garlic powder. Also, in my opinion Sargo become more active when sea is dome & rough , weather is dull and takes air mostly in rock bottom. Lastly, use circle hooks to avoid hooks break from Sargo strong & sharp teeth.
