I recommend 21/25 ct. shrimp. Boil, peel, and if you’re the persnickety type, devein, but leave the tails on For five pounds of shrimp, mix well a cup of rice vinegar, a cup of vegetable oil, a small jar of capers (with liquid), two tablespoons of good Italian herb blend, a thinly sliced onion, and a teaspoon each of coarse black pepper and red pepper flakes (or to taste). Add a small white onion, very thinly sliced, two fresh bay leaves, and a cup of diced mild peppers. Toss until shrimp are coated, cover and chill overnight, stirring occasionally. In season, add diced ripe summer tomatoes before adjusting salt and spooning over leaf greens and drizzling with marinade liquid.
