Well, yeah, "schon" can be used in that second sentence, but that's not what I was aiming for, I'll try to explain the whole thing a bit better:
Let's concentrate on the first sentence: "Oh, that IS big, all right!" (or maybe "Oh, that's BIG, all right!"). Another way you could say this in English is "Oh, that SURE is big!"... It has the same meaning AND similar tone/style. Now, in German, I could say something like "Das ist wirklich groß" (or something like that), which would basically mean the same thing, but the tone/style would be different. What I'm looking for is a way of keeping the tone/style of the original sentence.
Maybe you could use "aber (so) richtig/echt" instead of "richtig/echt" to make it sound more colloquial: "Wow, das ist aber ein richtig/echt großes Glas"
"Wow, das sind aber richtig/echt umwerfende Neuigkeiten"
"Wow, du scheinst Katzen aber so richtig zu lieben"
Another translation of "all right" could be "ohne Zweifel" or "kein Zweifel".