Full Range comparison

With the 300b tube, I would plan on adding a powered subwoofer (now or perhaps in the future after listening a while in the space).

So, if full range, or any other speaker design, low bass is less important than you would think. The space often reinforces low bass, beyond printed specs.

I would still go for efficient speakers with low to mid power tubes. 

@ Elliott
Yes I was aware the 300B has its limitations on low , deep bass, , at least on most speakers,,,92db+ is my guess best for 300B tube. 
I am thinking to add a  845/300B amp, 
Either the Line magentic 517, big brother to the 217 @$2K or the Cayin 845/300b @ $3K.
I am hoping either will drive the highly INEFFICIENT Thors rated 87 bd. 
I would hate to adda  845 and the sound is anemic/dull/flat in full orchestra, As that amp can not be shipped back to china fora  refund = both weigh in at over 60 lbs. 
and I  would hate to attempt to sell the amp on ebay ata  30%+ reduction. 
Shipping, as you know has gone wayyy up with FEDEX.~~~ 70 lbs = $275 ship. 
I've never heard livea  845, only via YT. 
Most of the 845 vids on Yt have horrible sounding speakers,,,speaking of which,,,have you guys seen the JADIS room YT upload ata  LV show??? 
Jadis has  the worst sounding speakers IN THE WHOLE WORLD. 
Also there is a  YT upload with the Jadis 200 monos, + Jadis' 4 chassis pre,,,what a most horrific/disgusting sound,,,not sure if it is the speakers or the jadis. 
Calss F sound. No wait its the Jadis 500 monos, each weighing in at over 120 lbs each (a  bit exxagerated , but only bya  few ozs = yeah i am bashing jadis, although i do know they make the worlds best sounding intergrateds, yet very expensive)


Jadis 500, puke sound


https://www.youtube.com/watch?v=j4lhlNppo3w

Look I am trying to take all newbiews and the old timers, up to CLASS A. have you ever heard of 

~~~~DISCRETE OPAMPS~~~~
No? 
Well neither have thousands of others..I JUST TODAY made the discovery, 
You need to go count all the 2 cent opamps in your CD player, takea  pic, with #'s to 
~~~SPARKOLABS~~~~
He will match it up to his inventory,,either singles or better duals.
I have just order 6 singles for my state of the art 
~~~CLASS A~~~~
Cayin 17, made 2003...Mark 1,,,the new Cayin 17 Mark 2 is out, sells for just a  few bucks over what I paid. 
Built like all Cayin, has dual top line of the line trans. 
Weighs a  hefty 20+ lbs. = a  beast.
With new opamps, + new Mundorf;'s = class a