to be honest with you, to say to you "use PATCH X" is wrong because every song is different. not all vocals will benefit from a large hall reverb!
i dont really use the MPX100 for anything else but delay cus the 460L has the reverb tasks. but....
here are some good patches for vocals...
PLATE REVERB - variation 8
PLATE - variation 2
PLATE - variation 5 (sometimes...)
CHAMBER - variation 15
for backing vocals, there's a cool chorus patch.im not sure which one though, check it out
bear in mind, these settings wont work for every song. take some time out, play around with the settings. there are some great delays. the inverse delays are cool on dance music.
-Romesh
Long Wave Studio