I’m not sure why that model would be any more difficult to sell than any other discontinued/superseded tube amp? Tube amps are generally a hard sale due to weight/shipping, the particular fickleness of this segment of market, and recent skittishness around tube supply (overblown IMO). At 53 lbs per side it’s a lot easier to ship than many in that power class.
If you already like your exiting CJ amp, that's good reason to stick with the brand. Hifishark can be used to at least ballpark how much to expect on a resale.