If a 10W amp is accpetable, the Guinevere PT can certainly do the trick. U-L rigged 6V6's with E-Linear connected front ends come to mind. With a special modified version of a Peerless 16309 ( the OPT from the W5 ), it would be pretty hard to top. Special attention to screen tap location is key. According to the Lit review I have done for the 6V6, it looks like 20% is the magic number. Hopefully somewhere between 20 and 25% is easy to get with that Iron. I know it is for the bigger S265. For additonal use, and for additional experimentation, it might be best to get more than a single set of taps.

I don't like to use a lot more Iron than the job requires, but the 265's have done well for me in designs yeilding 6 Watts, so I am fairly comfortable rcommending this particular Iron for a lot of different apps.

For example, the WE sheets give SE operating points for the 300B at 5k loads. For class A PP, this works out to 10k for an equivalent load/condition.

There's lots of options, and a complete and thorough understanding of the end-use criterea are critical to making a good design. We certainly did some revising fo the original, minimum cost version of Guinevere. A similar process will yeild good results for the amp as well.
regards,
Douglas