i generally like to kind of monitor the GR meter and make sure i am not comping at the biggest part of the song by 4db as i find the api is a bit more aggressive than the ssl to my ears at least which i feel can comp to 6 even for metal if it calls for it. but it's personal taste.
i like like 4db GR at 3:1-4:1 with attack and release set accordingly but generally they are pretty moderate with the attack on the slower side like 30ms or so and a pretty fast release.
i like the soft knee mode with no thrust and the "new" feed forward comp.
and i leave push in the manual gain make up and leave it at 0, or sometimes i'll let it auto gain makeup depends.
the api seems a bit more aggressive to me wheras the ssl kind of smears and smacks it more whereas the api like pummels and squishes so i dunno it's subjective and i don't have enough experience with bus comps to be talking just kind of sharing my insights.