NOS would be the best choice, e.g. RCA or United 845s. For 300B's, I am partial to AVVT (again, basically NOS, as they aren't made anymore). WE is also a good choice on 300Bs but even more $ than AVVT or EML.
Marty, I am using new production Cetron 845 tubes in my 211 AE's and I switch between the Sophia Mesh Plate and the Sophia Carbon Plate for my 300B tubes. No way can I afford the NOS 845s and I found that the new production WE 300B were crap. I have not tried the Sophia 845s but I do highly recommend their 300B tubes. Those are great amps. I love mine.