Advice using electrostats with tube amp.

The Theos has an impedance of .8 ohms at 20khz. It’s not a 4 ohm speaker. Still many people like using tube amps with MLs. I don’t think it would hurt to try your tube amp with them, but I would try to get my hands on a solid state muscle amp for comparison.

"Sfall, the room is about 15X20' with 8.5' ceiling but my listening position is only about 13' from the speakers and i dont listen at high volumes. I agree withyou, then, that it should be fine but because the purchase is not a small one for me, I'm trying for all the advice I can get. Thanks"

You'll be OK. I've powered ML's in a room that was a little bigger, and with an amp with less power than yours.

I need to make a correction.  Although it would have no bearing on the subject of impedance, the speakers in question are the Ethos (not Theos) which, as well as with the Odyssey's before them, I had been using with the Peachtree 220 amp. Today I'll be transporting the Cary to the guy's house who has my old  Ethos for a trial. Room acoustics there are significantly different than mine but I should get some idea about the overall sound. Also, I've been running the amp in triode mode with the reference 3a's and someone suggested that that switching to ultra linear may make a better match. Using the 4 ohm posts also came up in that discussion.  BTW, I've used mostly panel speakers for over 40 years (Acoustat, Magnepan and ML) so my familiarity with them is the only reason I'm even at trying this. I really thought my current setup would be the forever one. We'll see. 

I believe Ralph of Atma-Sphere recommends using a Zero Transformer when running difficult loads. He has a FAQ page on his website that will link you to it. Let me know if you can't find it.
B

I'm guessing you have an issue with high frequencies. If that's correct, I think the ML's are a pretty good choice. Personally, I find the main reason I'm drawn to an esl speaker is that they don't have a tweeter. The highs are much more realistic and natural sounding.