4 or 8 ohm connection for a 6 ohm speaker?

Yes, I normally spend my Summers fishing remote places in British Columbia- this year not possible, so I am missing the fish, beautiful country and charming Canadians.

Bill: 80% of the sound of a conventional tube amp is the quality and configuration of the output transformer... in essence you switched transformers and in essence amplifier so a change in sound makes sense.

Roger Modjeski ( music reference ) advocates light loading but also listening. Clipping is bad, so listen for that also. I light load my Vandersteen TreoCT ( an engineered easy load at 6 ohm nominal ) with the 2 ohm tap on my RM-9. Amp stays in class A longer and at the relatively low volume I listen at - sounds better.
have fun - enjoy those great speakers! And the music !