Ben Levi, for Orach Chaim the yeshivishe velt follows The Mishna Brurah. As he did not write on Yoreh Deah we follow the Chayey Adam, Pri Megadim, and Aruch Hashulchan, along with the psakim of Rav Moshe Feinstein zt”l. The Pri chadash also reads the gemara kepshuto, but says as we are mekulkal we shouldn’t follow it. Rabbeinu Ephraim does as well, but says it’s not lehalacha. I do not know what the Ben Ish Chai says lehalacha, but as I’m a litvak not a sefardi it’s irrelevant.
Volvie, if I’m attacking a straw man, what IS your position? how much should one drink? I’m sure you agree with kol hani poskim I quoted, so I’m interested in hearing what you ARE espousing, and why it’s therefore muttar to give a drink to a minor.