What is the minimum Shi'ur (volume) of a cup required for making Kiddush on liquor? Is there a smaller amount required than there is for wine?
What is the minimum Shi'ur of the liquor that one is required to consume? (And is it dependent on the size/fullness of the cup? Ie., if the cup is larger than the minimum volume for the cup, and full, is there a percentage to be drunk, or only a volume requirement?)
I originally made these separate questions because this Shabbath I saw, for the first time, someone make Kiddush on liquor using a full cup, even though the cup itself was much more than a Revi'ith, which is a stringent approach, but then only drink Rov Lugmo (basically a mouthful), which is a very lenient approach. I asked him if he intended to drink Rov Kos (a majority of the cup), a stringent approach in line with the fullness of his cup, and he specifically said he was Meikel on that and specifically only drank Rov Lugmo. This made me wonder if there are sources that separate the two (three?) issues.