How many tube watts for Vandersteen 2's?

It's really more important that you have some current behind those watts. For example, you could use a pair of Dyna MKIII's but you won't like the way the bottom end sounds. Sixty tube watts is sufficient if you don't play your music loud. Just use a tube amp that has some decent energy storage. Most of the ARC amps do. Roger's amps do as well i.e. RAM Labs/ Music Reference. Just remember, current controls the bottom end on dynamic speakers.

Yes the VTL IT-85 is sufficient.

I am using 2cesigs with a Music Reference rm9 mkll and I couldn't ask for better. The bass is as much as I could ask for. The Rm9 is the only component I never think about changing.

Believe it or not, the best I've heard Vandersteen 2s (and I've heard them a lot) was with a 35 watt Music Reference RM10...

This is really good to know since I've been itching to get the rm10 but was worried about it driving my Vandys 2ce sigs. Think they'd do fine in a larger room, 20x35 at moderate sound levels? [Sorry to distract from the original question.] rm9's are hard to come by.

Those 35 watts are magical, though Roger would say "nonsense" to that. But I think it would work for you. I owned the Music Reference RM9 Special Edition which was a limited run ($10,000), point-to-point wiring version of the RM9 with a different driver stage than the std RM9s, that put out 162 watts into 8ohms. It was one of the finest amps I have ever heard - the RM10 was good enough to let me sell it, something I never thought I would do. Buy one used, you'll sell it in a few hours if it doesn't work for you in your room - only you can tell. You could also get two and run them in mono for 70 watts/8ohms if you love the sound but just feel the need for more power. Roger had them on sale for $1550 during the recession, might still be able to get them at that price. I use mine with Merlin VSMs which are more sensitive and an easier load, but I run it off the 4ohm tap which drops the power to 27watts (but more current reserve)and it never, ever, seems to be running out of juice. I think Richard recommends 40 watts min with the 2s, but I would trust Trelja's observations (they are tube watts afterall.)