Question How should I set up my VoiceLive 3 to run through my amps effects loop 

Answer You can try one of these two methods:  EITHER: VoiceLive 3 Guitar OUT Effects Loop IN Effects Loop OUT Voicelive 3 Guitar IN - guitar straight into Amp IN OR: guitar into VoiceLive 3 Guitar IN and then the Guitar OUT sent to the amp's Loop IN.   Both the ways described are viable: however, with an FX loop, you will probably want to go like this:
  • Guitar into VoiceLive 3 
  • Guitar OUT from VL3 (mono) 
  • FX Loop RETURN on the amp
What that does is bypass the preamp in the amp and goes straight to the power amp. You can then use all the effects in VL3 (you might want to turn off speaker sim in the setup menu) without going through the preamp in the amplifier.