What is the preponderant opinion regarding the number of takbirat in the first and second rak'ahs of the Salat al-Istisqa?

Scholars have differed regarding the description of the Salatul-Istisqa (Prayer for Rain). Some have gone to the extent of saying that it is like the Eid prayer, with seven takbiraat in the first rak'ah and five in the second, and this is the most preponderant opinion due to the statement of Ibn Abbas: "And he prayed two rak'ahs just as he used to pray for Eid." Others have gone to the extent of saying that it is two rak'ahs like the supererogatory prayer, without takbiraat. However, the Salatul-Istisqa is valid whether it is with takbiraat or without them.