I wrote in March/April about using the dpa 4099 hypercards along with omnis (DPA 4063s or Sanken COS11s) four track, and taking the bass (from about 250 Hz down) from the omnis to fill out the 4099 recordings, I did this from March through mid May in order to bring opera voices upfront and personal (I offered sets of recordings here and a couple of TS folks requested them, but I've had zero feedback so far from them).
Last week I had a situation where I was no longer up front, but had to tape from upstairs (though forward and to the side). I decided to go four track for this as well, since omnis don't cut it for me when too distant. I ended up mixing the two sets of tracks without any EQing, on the theory that since the omni and hypercard cap were only as far apart as the halves of an mK4 cap, for example, I'd have a little less directionality, more like a cardioid cap, from mixing them, while also getting some help in the bass from the omnis. I am very happy with how this turned out, way better than any tiny cardioid I've tried. I'll have to listen to the mix after a rest to see if it still thrills me as much (and if my pro friend validates on his high-end monitors my non-objective response), if so I have a new alter-MO.
Jeff