The largest recognized shiur is that of the Chazon Ish,tz’l
5.3 fluid oz.
But unless you drink the entire cup (and you would have drunk the entire cup using a cup with a smaller shiur) then by using a cup with a larger shiur you give up one Hiddur Mitzvah for another.
In the words of Rabbi Doniel Neustadt:
“Those who are particular to use a large size cup in order to satisfy the opinion of the Chazon Ish but do not drink the entire cup, are in effect substituting one chumrah for another.”
And if you ARE going to use a large cup AND drink all of it, you might consider a low-alcohol content wine.