I'm not dying to match it although having that exact tone would be awesome, but I'd to get in the same area. Apparently he used a Phase 90 set pretty low for the solos and a chorus for everything - which chorus I don't know. Not in the market to buy two new pedals, and I could try to find both a phase 90 and a chorus used (if anyone has one or the other or both, PM me), but if I get one, what should it be? I know a chorus really beefs your tone by making it sound doubled.
Pics of Zakk before he became a complete lumberjack-dick:
Based on the time and his old habits, he probably used an old Boss Chorus pedal.