You have a maximum of 4 different FX built into the Qu-16. Standard practice is to use one reverb for ALL vocals, perhaps a special reverb for snare or something else and a tap delay. The fourth effect is usually a second vocal reverb with a different decay so you can easily choose long or short tails.
If you want more, you’ll have to find some way to add outboard processing and use up some of your Mix sends to feed them and return them through either ST1/2 or bur an input channel.
Four should be enough for practical live sound. Try reading the manual…and good luck.