I've decided to try Tubes

Look for Triode Labs El-84 amps, used, for a stretch of your price. (See 6-Moons review.)  Or, Decware Mini Torri MkII El-84's \the best choice of a top speaker placement specialist I'm aware of (on Def IV's, in Atl.)  (Not me, though I do own Def IV's...Tannoy Churchills, lots of Living Voice, Opera, Totem & DeCappo). They're a good start, you'll might move to 2A3's or OTL's later for a little more extension or transparency but with a loss of bass solidity. - Don't think these smaller output tubes don't do bass.
El-84's were what some of the best amps "of the day/back in the day", Scott Amps, used. Don't count them short. -About 20 push/pull watts. "Good" is  still  Good.
(I too, think the Zu speakers are a bit less efficient than they claim to be.)

One question for Tube owners. How long do new tubes typically take to break in. I've rbeen ad that some high end Gold Lion tubes need a couple of hours of burn in time to open up.  Just curious

After hearing a Linear Tube Audio amp, I sold all of my Decware gear and rebuilt 2 systems. This LTA stuff is incredible.

Did you pop a cookie after you heard them!!

@aberyclark I've personally found tube burn in to be a fairly subtle thing, a good tube will sound good from the get go, and will certainly open up a bit as it burns in. I don't think it changes the nature of the sound that much but it does improve. Just pop the tubes in listen and let break in take care of itself. As with all things YMMV.