Staccato choirs are tough to get to sound good, but you can do it for free, no words, but stong hits of ahh's are easy. Download Magnus Choir, and find a couple of different soundfont files and turn one or two of them up really high and put a shit ton of reverb on them. Then just adjust your timing on your louder channels to hit really short and sweet and make your softer channels hit longer more drawn out notes, then you have your hits a bit more dynamic.