Well, recently I've bought a BOSS MT-2 Metalzone pedal. And I have a ROLAND CUBE 60 AMP, trouble is I cant get the sound I want at all. I'm using the JC CLEAN setting, instead of LEAD [The setting you can use all the effects] so the effects on the amp don't mix with the pedal.

Anyone got any tips, should I be using JC CLEAN? or go to LEAD.
I'm looking for an overall heavy sound, for death metal/hardcore on my guitar. If anyone can give me the right settings for the pedal and the amp if necessary then I will be very happy. Got a gig with my band next week, and I'm in desperate need!