My guy said late June would be the very first DK HST shipping, more availability in July, and good supply/availability in Aug. I wasn't in huge rush for replacement, but didn't want to wait until Aug either. I would bet you'd have to go to a bigger volume dealer like Larry Stoves Equipment or similar to get one of the first available ones.
My NX finally got delivered today. I'm not super tech savvy but will get a few videos of it on youtube from me tinkering with it today.
That price you got for the CK would make it a real tough call for me. IF you don't need all that loader capacity, I would guess you will still get everything done on the CK. I'm sure at times you might wish you had just a little more and think "I should have got the bigger one!"....but that's a huge cost saving as well so might be worth it. I went back and forth with the price difference between CK3510SE and NX a LOT trying to decide. Kept coming back to "I can rent a backhoe a LOT of times with that price difference and still come out ahead". Do that for the big projects, day-to-day stuff with the CK. But ultimately I just move so much dirt and IBC totes with water, I really figured it was worth the cost for the bigger machine since I would be working around the CK limitations too often. So really depends on what you need the machine to do.