I'm acquainted with many meanings and uses of bereits, gerade, schon and gleich; but sometimes some of these words are equivalents and sometimes not; and sometimes, too, they may entertain more than one meaning. For instance:
Als ich zur Party kam, waren die meisten Gäste bereits heimgegangen.
Does this mean: "... most of the guests had already left" or "... most of the guests had just left"? And, in German, which would be a more exact synonymous: "... waren die meisten Gäste schon heimgegangen"? or "waren die meisten Gäste gerade heimgegangen" or "... gleich heimgegangen"?
It seems to me that, in the case of Perfekt and Plusquamperfekt, gerade means the same as gleich and bereits (already with the addition of just a few seconds/minutes ago), and schon means just already.
Is my thought correct?