I have a couple pieces of advice:
1) I find 13-25 to be the most reliable on the opening trill, having formerly used 23-15 and experiencing various levels of (un)evenness on each piano. Furthermore, 13-25 is a very different movement than 23-15 and I find that it has a better sound.
2) Think polyphonically - some hear the piece with a succession of thirds, rather than two lines harmonized at the interval of a third. Along with this goes the notion of subphrasing, which helps in any kind of run (both double and single notes).
3) Last, but certainly not least!: Have a "sound image" of the piece, i.e. a musical idea for it. It helps tremendously to think in terms of sound colors and phrasing, rather than in movements and technical difficulties (though it is true that some time must be spend on these things so that they can be solved and the music freed).
All the best to you!