Depends what emulator you're using. The on board distortion with a bit of muted doubletime delay sounds mint on the ABL. Light flange and chorus is also good. IF you wanna go out there get hold of the hematohm plugin.

Usually high res, low cutoff varying mod wheel to taste. Just stop when it sounds good.

I usually automate one acid line and do the second run manually to give it an organic flow. Layering a thrid line of acid stabs sounds cute too.

You'd be surprised how little effects usuage you need to tilt the sound to filthy. I used tyo cake on the distortion but have found a whole new range of filth by being sparing with it. It will improve the sound quality too. I don't recommend compressing acid lines. IMHO anyone who does is plain wrong.