SET suggestions up to $3k (used)

Dennis Had Inspire SE 6550

Don't know the size of your listening room or your preferred listening level. I'm thinking you're on the right track in thinking 8 watts. I drive 93dB efficient JBL monitors with my ~7 watts of SET 300B power and really enjoy it.

I think you're in a target-rich environment, though shopping might take some patience. Just keep checking all the various audio sales websites. The equipment is out there.

How about considering a solid state class A integrated such as the Sugden A21se? It can be had for $3250. It is 30 watts of pure class A, single ended. Unless of course your heart is set on tubes. The Sugden has a similar sound to a tube Amp, without the hassle of tubes.

Maybe a used Line Magnetic with more power.

I use a 4 watt Deware Mini Torii with my 92db Ref 3A de Capos

plenty loud in a 22x12 open room