Instrument EQ: in group, or separately?

It's never made sense to me to EQ both sides of a stereo ANYTHING the same. The way I see it, you have two scenarios. One, you are using two different amps, which are two different sounds, and would need two different treatments...or two, you're double tracking the same amp, in which case you'll get a better stereo image if you EQ them at least slightly different.
 
It's never made sense to me to EQ both sides of a stereo ANYTHING the same. The way I see it, you have two scenarios. One, you are using two different amps, which are two different sounds, and would need two different treatments...or two, you're double tracking the same amp, in which case you'll get a better stereo image if you EQ them at least slightly different.

When using two different amps I eq them in a different way first, as you said they need different treatments. When it comes to double tracking with the same amp I prefer to have the same settings in the tracks. I most of the cases tracking the thing twice is enough to have a bigass stereo image even if it was the same amp and guitar... But it depends on the song and the desired sound. My point is, I like to approach mixing guitars as if they were one big instrument, especially in metal. So I often put one colouring EQ for all the guitars too, to kind of glue them together.