High powered single end 300b recommendations

There is some misunderstanding between amplifier power and speakers sensitivity. The combination of these two parameters plus listening room acoustic characteristics like the Critical Distance give the maximal listening volume. 
There is not direct correlation between speakers bass control, speed and dynamics with amplifier power. 
In many cases it depends more to amplifier schematics and power supply design. For example, in mid size room speakers with 94dB sensitivity can sound better with 845 SET vs 300B SET not because "8 watts is not enough" but because 845 SET has more energy storage in power supply, interstage driver transformer and strong driver tube (for example 300b)  vs weak (for example 6sn7) driver in 300B SET.

Allnic A6000 monoblocks are rated 60w using EML XLS tubes, 4 per side. They also have a toggle for negative feedback and no negative feedback, which helps with more difficult speakers. They sound fantastic if you can find a pair. 

I have Altec 604E speakers in a mid-sized room. The real sensitivity of these speakers is ~97db. I drive it with a 6 watt 300B DIY SET amplifier with EML mesh plate tubes. I did experiments with changing 300B B+ power capacity. I started with 100uF per channel.
Then I went to 350uF electrolytic capacitors per channel. Next time I added 130uF of polypropylene and oil capacitors.
Each time I got very significant improvement in bass control, dynamics, separation, soundstage. The difference was much more significant compared to changing James Audio output transformers to Hashimoto H30 which cost 3-4 times more!
In the end I added another 1600uf of electrolytic CDE capacitors per channel and got another level of clarity, focus and bass control. The same happens when I added capacitors to the driver and input stage B+.
The difference between the initial variant of my amplifier to my amplifier now is huge. It is like its cost has increased 10 times.
I can’t imagine my speakers are capable of such bass performance with any amplifier.
I don’t understand why producers save on power supply capacitors. Why instead of going to the 845, 211 tube models don’t build a good power supply for 300B or 2a3 amplifiers that had much wider bandwidth, less distortions and a lot of other advantages.

Wyetech Labs is worth looking into. They have (2) 300 B mono block amps that are superb and produce about 23 watts per channel  running 2 300B tubes per channel.

Aric Audio will build you a very nice PP 300b.