Hi
Usually the best way to record an upright piano is to put the mikes over the open lid, one for the higher side, one for the low keys, spreading them apart as needed to get the correct stero image without phase issues and starting with a distance of 10" from the edge, going away for a more overall sound, as the closer approach will result in a very defined sound with lots of hammers click; I never tried to use stero techniques on an upright piano, but who knows, it could work OK, just try it.
For mics I'd go with a pair of large dia condensers like Neumann U87 or TLM103 (expensive) to AKG 414 B-ULS (middle of the way) to budget mics like Audio Technica 3035 or Rode NT1000 (which IMO are still very good sounding).
As good as condenser mics can sound on piano I heard one of the best upright piano recordings made with a pair of Sennheiser MD421 (dynamic), for a pop context.
Hope this helps
L.G.