How do I get a great Metal Tone? I'm trying to get a great Metal tone on my new Dean Vendetta XMT guitar with a Zoom Fire 30 amplifier. It has built-in tones like Metal, Fuzz, BG, High Gain, etc. but it also has Gain, Bass, Middle, Treble, and Level knobs with delay and reverb switches. I'm looking for a tone similar to Synyster Gates's. Any advice helps.

PS, Some of my knobs go from -15 to 15, some go to 1-30. Not exactly sure why, and I also don't have any pedals.