Don't remember Guys that 80% of Your guitar tone comes from Your... hand
IMO, You could copy all if the Petrucci's settings, bought same amps, bought same guitars, strings, cables, effects... and still, Your tone would be different than true JP's tone. The same goes for all other instruments IMO.
And about AxeFX, my guitarist is using one of these live, studio and in home and it's great. It's expensive I know, but if You're playing live, and studio and want to have all Your settings in one place - AxeFX is the answer. Of course, You have to spend days to set it as You want, but believe me, it's worth