It works ! I successfully mounted the 7-speed cassette on the new Wahoo Kickr Core and it works great. As the video previous referenced asserts, it required a 4.5mm spacer with notches ground out for the cassette rivets (see spacer and cassette pictures). I used a Dremel to grind down the notches and it was easy to align the notches in the right spot behind the cassette. I’ve also included a picture of the bike mounted on the Kickr Core.
Ultimately the Kickr Core rides sooooo much nicer than the Kickr Snap. Far smoother and most notable is easier. Given today’s training plan workout and how it felt vs previous workouts, I’d estimate I was consuming about 5% power in the friction and deflection of the tire on the Wheel-on trainer roller. That power is not measured or seen by the trainer or therefore Zwift because it is occuring outside the measureable system. It’s possible the spindown test tries to account for this, but I definately felt a difference. In the end, the change to Direct Drive, even with just a 7-speed bike is well worth it.
