I have:
  • Ibanez S2075FW Prestige
  • Marshall MG100FX

Advise good metal pedal
Honestly, from my experience and many others aswell...

You will not find a pedal good enough to make a MG sound good.
-Gibson Les Paul Studio Cherry Sunburst w/ Alnico Pro II
-1960 Yamaha Orange Sticker Acoustic
-Marshall JCM2000 DSL 401
-Fender Hot Rod Deluxe
-Blackstar HT-5RH
MG distortion is no good for metal

I'd get a different amp.

Not sure about the AVT, some people like them others don't, it's more preference.

The MG is nearly (if that) impossible to get any good drive out of.