Choosing the right plums is key to achieving a well-rounded flavor profile for your sauce. Opt for ripe plums, preferably varieties such as Damson, Santa Rosa, or Satsuma, which are known for their sweet and slightly tart taste. The plums should be firm yet juicy, ensuring they contribute the ideal balance of sweetness and tanginess to the sauce. Remember, the quality of the plums will directly impact the final result, so select the best ones available.