The price of new production 300B tubes has really escaladed over the last couple of years. I remember when a top China 300B could be has for $200/pair. European 300B, EAT, AVVT, EML, KR Audio have always been around the $700/pr mark. China and now Japan has seen a great appetite for premium 300B tubes and have marketed these tubes primarily to the US marketplace.
I am not going to comment on the value proposition of these new production tubes because price performance is purely subjective. I have listened to Takatsuki and they are indeed a superb tube, but at a price of $2,000/pr, they now make some of the European 300B look like a bargain.
On the plus side, 300Bs last a very longtime; therefore, the sting of price can be offset with the number of years of enjoyment you will get.
Also, from what I have read, 300B in PP configuration run the tubes harder when compared to single ended, therefore, an XLS tube may be better suited for your application. Take a look at the Canary specs to see exactly how the tubes are stressed. Take your time, and see what other Canary owners are using.
I know that before Coincident started marketing their own amplifiers, Coincident used Canary amps with KR 300B.