@ulcerdoc the key to the ref 10 and VTL 6.5 is lower PS noise floor. As you lower the noise you get better resolution. The other factor both offer is much wider bandwidth than either of the others.
Another option would be look for a used VTL 6.5 series 1. They come up every so often for sale in the 3.5k to 4k range. at that price point not much will touch it.
There are also improvements you can do to the Chinook to lower its noise floor.
1. add .01uf bypass caps to the rectifier diodes to lower their noise floor.
2. on the rear input panel replace the metal film loading resistors with Vishay S102 foil types. This alone will lower the noise floor 2-4 db over metal film.
I was in your boat a few years ago. Had moved up from the Chinook to the steelhead. Was quite happy with it. Until a friend let me borrow their TP 6.5 series 1. It was a 2 second test. After that was tough to return to the steelhead.
I'll be the first to admit it was a tough pill to swallow since I was set on the steelhead and thought it was my end game phono stage.
The REF 10 is new enough may be tough to find one on the used market.

