Okie its pretty straightforeward.
If you are talking about Slash's tone as in the guitar intro shred in Sweet child o mine...
Okie... Its pretty straight forward....
If you want to even be "THERE" in slash's tone... You will at least need a TUBE something.... either tube preamp, tube amp, tube power amp, tube pedal tube whatever.
Next you'll need humbuckers and Les Paul. You'll never make it with a single coil strat.
And for the settings part. The EQ!! you have to use your Ears!! To figure out, all amps and speakers and Pauls are different, I cant fix it for you every single time. you have to use your own ears to tweak. Thats for the EQ.. Be it post EQ or pre EQ, its up to your ears.
The trick that slash uses is the tone pot roll off. You set your paul to Neck humbucker, and roll off the tone knob. (meaning you set it to 0) It'll sound goddamn friggin warm.
And you'll set the tone from there, be it your AMP, pedal, eq, whatever, you tweak your dist tone from there.
Slashes sound is definitely tube man... So its friggin hard to imitate unless you really got a friggin tube. or a super cali fucking good ear.
When you need to get to the friggin steaming WAH solo part of Sweet child, just give your pickup switch a slap and bring it to the neck mode. You'll be shredding like slash in no time.... (provided you can shred in the first place) 8)