How many tube watts for Vandersteen 2's?

IME 60 watts in plenty for the Vandersteen 2s. They are easy to drive with most tube amplifiers. In the case of the M-60 you don't need the ZEROs, in the case of the S-30 I recommend trying it both ways and see.

I had Vandersteen 2C Sigs powered by a 45wpc CJ CAV 50 and this was plenty for them.

Well, I just bought a RM-10. So, I'll see very soon whether 35 tube watts can drive the vandies in a sizable room. Fingers crossed. Will report back.

I have the Vandersteen 2CE Signature II and I was driving it with the NAD 2100 that are set to Bridge (mono) at 300wpc. The sound is awesome and I love it. BUT, when change the NAD to my old McIntosh 2100 rated at 105wpc in stereo mode, the sound became more alive as in the low bass is a lot fatter and more natural and cleaner mids and highs. But if I or you guys can get a tube amp, it will even sound better I mean a lot better.

Full day of listening to my newly acquired RM-10. I had it light loaded on the 4ohm tap for the 7ohm rated 2ce sigs. After 4 hours like that and being rather unimpressed by the sound I was getting, I used the 8ohm tap. Far superior in my set up. Sound opened up and more dynamic. I'm not drawing any conclusions obviously but I'm not too anxious to go back to the 4ohm setting either. With my LSA passive preamp at 2-3 o'clock the amp had plenty of juice for the Vandersteens in my sizeable room. The bass is surprisingly tight and full. Any edginess and brightness that I used to have with my ss amp is pretty much gone.