Yep, the KEF is rated at 93 db sensitivity so with even modest power, reaching high volume would not be a problem. And no doubt that the push-pull KT88 amplifier is more suitable than an 8 watt SET  amp.
Charles
I received the Muzishare X9 today..It is very good and comparing to X7 it is bigger in every size, dimensions, tubes, transformers, knobs etc...and sound bigger too. First day test I noticed that X9 as SET is more picky on the speakers and the speaker ohms. I will keep testing and roll some 6sn7 and 6sl7s first etc...
@cb3489, 
Congratulations!
As long as the 300b SET is paired with appropriate speakers I believe that you'll be quite happy with it. Are you using the KEF or have you received the Tekton Perfect SET?
Charles 
@charles1dad 
thank you. Using 105/3s in 4ohm mode. 8ohm mode some how generated distortion after 11oclock level. As expected Kefs wants lots of current i assume. Tekton perfect set 15 i ordered,  12 weeks wait time so another 9 weeks to go. That would be a great test. I also test audioquest and requisite cables. Ares ii and raspberry pi streaming stays same. X7 is really good too but X9 sound debt and larger sound is good. Big price difference though X9 is 1k more. I guess we get what we pay for. Both are amazing value. I need to figure out how to share photos here. 
@cb3489,
You have 2 very capable amplifiers, however I do understand the allure of the SET and why you are drawn to it. This type of amplifier if executed properly stirs much musical emotion and gets you more involved/connected with the music. I would be surprised if things do not further improved once you receive the more efficient  Perfect SET speakers. It’s impressive your SET is doing this well with the KEFs.
Charles