Help with speaker selection

I'd ad Vandersteen Quatros CTs. They're in the 17k range I believe. Vandys are well known for their musicality and listenability but when they add carbon tweeters to a speaker the detail is amazing. They also have room tunable subwoofers built into each speaker to allow you to mitigate room modes some which really helps with bass definition. Take a listen somewhere 

Your JC1 is a musical amp. You do not need musical speakers like sonus Faber it will be too warm unless you bipass Olympics and go to the more hi fi and accurate Serafino.
in your budget I would look at about an 18-20k pair of Vivi Audio Kaya 45. They will open up better and have good synergy. They are also easier to drive and you won’t need JC1 just a JC5+ stereo amp.

If you stick with the JC1 Vandersteen Quattro will be also amazing with that amp. They are phase and time aligned and need a lot of power.

For resale another good speaker is the new 45k Wilson Audio Sasha-V but that might me over your budget. The smaller Wilson’s don’t have the bass.

I re read your OP. @hk_fan I also researched your implied speakers, and I agree with @mikekollar You should research the Legacy Audio Speaker line. Your JC1’s will drive them just fine, Suggest you consider the Focus XD with Wavelett II or if you want to go all out maybe the Aeris. The Wavelett II is the icing on the cake IMHO. This brand flies under the radar to most audiophiles but has many raving fans for those who try them. The attributes you are looking for in your post are up their alley. Revealing, dynamic, bass definition and slam. hey will fill your large space easily. They are made in the USA so the cost of importing from Italy for example is not included in their price, they are a bargain.

Gershman Grand Avant Garde. Very musical and well within your price range.

https://www.soundstageultra.com/equipment/egglestonworks_andraiii.htm