Which is stronger Espresso or Ristretto?

Ristretto is a method for running espresso - meaning in Italian "restricted pour". The volume of water that flows through the grounds is restricted, leaving a smaller espresso shot - less than 3/4 of an ounce. A regular shot of espresso is pulled to one ounce or 1 and 1/4 ounce. Regular shots of espresso are often perceived as "stronger" although that is a subjective phrase, because of the higher levels of acidity - due to the water flowing through the grounds for a longer duration - pulling more salt compounds from the ground coffee during the espresso extraction or emulsification of sugar/salt compound process. There is even another pull called "Lungo" or "long-pour" where the water flows through for a final volume of 1 and 1/2 to 2 ounces. This is very watery, biting, soured espresso (due to high volumes of salt compounds) and is not popular in the states, but can be seen in Italy and other European countries. This would probably be perceived as the "strongest" of the three pours. ______________________________________________________