Triangle Theta vs. B&W 805D3 with Luxman tube amp


I'm trying to put together a small system for my office, 12x15ft room. 
I auditioned Triangle signature theta with Luxman SQ-N150. The combination sounded good to my ears. 
I'm also tempted to get 805D3 but unable to audition with Luxman tube. I know it is entirely subjective but I was wondering what is a better speaker for this amp? I understand BW is a more recognized brand and would probably keep its value better than triangle. Triangle has a metal tweeter, does It mean it's brighter than diamond tweeter on 805? How do these speakers compare in general? Is 10W Luxman good enough to drive either speaker? 
This system will be mostly used for Vocals and Jazz. I like to play loud, but also has to sound good on low volume at night.  Thoughts? 
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I don't know about that.  They are both very similar for impedance ranges (nominal 8 ohm with a minimum 4.4 or 4.6 ohm).  While the Theta Triangle is 2 db more efficient, 10 watts is not a lot of power to play with.  Keep in mind that tube amps will saturate much lower than rated power, so you really will only get about 5-6 watts clean power.  An amp like this would probably do better with a more efficient speaker (like 95-97db).
Do you think the Diamond speaker class is comparable to theta or higher end Magellan from triangle ? 
What about the horn tweeter on Triangle? Is it known to be bright ? Would a luxman tube amp tame that brightness ? I guess my question is which is a better stand mount option? BW 805d3 or triangle theta or duetto ? I haven’t excluded other tube amps yet. There is a unison research amp that sounds ok paired with triangle on YouTube. 
I would think almost any speaker in the db range of the high 90's and up would work well with the Luxman SQ-N150.
I am biased. I own the 805D3 as my secondary room setup. They are an astonishingly good, balanced, neutral speaker that sounds wonderful with a tube. If your room is relatively small, I think 10W is probably fine if you aren’t listening at very loud levels. You won’t be disappointed with the 805.