Second, the key to trey's tone is his Ross Compressor coupled with his Ibanez TS-9 tube screamer. If you want the closest you can get to the original ross and vintage ts-9. Keeley Electronics makes some amazing products.
Trey's tone is very midrange 7-9, with the bass and treble around 4.5
Trey plays Schaller Golden 50 Humbuckers through a 67 Fender Deluxe Reverb amp, with a bunch of modifications done to it by all sorts of amp doctors.
Trey's setup is amazingly complex, and it's literally a rat's nest of cables and equipment. I've tried to emulate it for a year or two, but what it REALLY comes down to is Trey's chops. It wouldnt matter if he played this stuff thru a junk solid state amp with no reverb, he'd still rip some very original tasty licks. I highly suggest you sit down and learn his complex compositions, and a lot of his licks will naturally pop up in your playing.
There are a number of options you could consider. Basically any combination of compressor and tube screamer is going to get you something similar. Trey also has a pretty sweet Digitech Whammy II pitch shifter that he uses quite a bit.
I know a lot more if you have any questions so don't hesitate to ask! :D
rarebird
