Which speakers will fill 5,000 cubic ft coherently

Tube amps employ an output transformer to match the high output impedance of their tubes to the lower input impedance of the speakers being used. These amplifiers have at least two separate binding posts for (usually) 4 or 8 ohms depending on the number of windings in the transformer being used at that impedance.
OTL (OutputTransformerLess)amplifiers do not have output transformers to adapt them to low impedance speakers. Sometimes an outboard transformer like the Speltz is used to compensate for a native mismatch but, as I stated earlier, that rather defeats the purpose of having an OTL.

Regardless of claims to the contrary, you will always get better results by optimizing component matching. OTL amps are better matched with HIGH impedance speakers. This does not mean that other speakers will not work but it does mean that they will not be ideal mates for your amplifiers.

>Anybody out there drive a Woodmere with any tube amp?<

I used to have my Woodmeres running with deHavilland Aries 845G SET's with absolutely no problem, whatsoever.

I'm now using a McIntosh MC 352 with the Woodmeres connected via the 4 ohm taps.

Fair comment, Macrojack.

Davvie- But don't some Mac amps have internal autoformers? I could be wrong, but I think I read that somewhere.

Denis- I think you should get the Selah's. I've always wanted to hear them and they are beautiful ;~)