try Decware for high-efficiency speakers that should pair well with your 300B. They also just released a 300B amp. Even made in USA! I have several of their products, and am not associated with them at all. Just a very happy customer.
Is there a 300B type amp out there with some WATTS behind it?
I recently acquired a Feliks Audio Arioso 300B amp. To put it simply, it is incredible. I understand one way to tackle the issue of using SET amps is with high sensitivity speakers. Is there a 300B or something that gives you that same sound out there with power so you have more speaker options?