Stereo imaging
I've been putting the imaging plug-in on the stereo out of a mix, when it's unnecessary on anything already panned. So it occurred to me to put it just on its own bus and to put all the channels that need it through that rather than directly to a stereo mix. Basically, anything centred other than bass and kick, but mainly vocals, synths, guitar solos and reverb channels. In terms of settings, use the mid and high preset, and increase the order parameter a little.