Midlandaudiox
Trade: Midland Audio X-Change
I’d say DeVore 096 or Harbeth HL5plus are favourable with CS300xsI got my 300XS from John @Midlandaudiox ,who is the UK distributor. He was a fan of the 300XS ( or the 600) and Harbeth. If memory served he recommended one of the larger models but I've been tempted by the p3esr as a second speaker option when they've come up here
But many more can work depends on your expectations of a full range speaker