LS50 won't sound good with classical no matter what you do. If you must stay with stand mounts you'll have to add a sub. But I'd definitely get rid of LS50 and replace with Harbeth or Sonus Faber. Alternatively, Focal micro utopia will sound much better than Kef. Here is one from audiogon in your range. Listen to samples on YouTube, you won't regret buying this speaker.