2) you can use the FX serial, as Insert effect, or parallel, using Mix->Return. The setting can be done when you choose an FX slot on the FX page and then you have to switch to the back panel setting screen. The mode and the channel or Mixbus configuration can be adjusted on that screen.
1) now we can answer the first question. When you use the FX with the Mix->Return Mode you need a send bus to sum the signals from allthe channels before you send that sum to the FX. The resulting FX Signal will be accessible on the Return channel for the FX and there you can adjust the amount ofthe FX for the Main mix or aux mixes (e.g. for Inear monitoring). I personally adjust the send level of theFX rather than the return level on live shows. This will cause a more natural Tail out of Reverbs or delays.
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