When we talk of common DHT for SET amps we, (I) mean 45, 2A3, & 330b.

I love the 45. My 45 DRD is probably the most "refined" amp I have but with my 96db speakers, they are more than sometimes, not enough. Even at very moderate volumes.

OK, flashback time. A few years back, when I thought to try the SET thing, I, as I suggested above tried it by inflicting it on my long suffering ST-70. I wired one EL34 across both sides of the output trans and let her rip. I liked it enough to pursue the idea. I had less efficient speakers back then and was used to 20-50W of P-P tubes and 250W of SS. So the 300b seemed like the only choice.

The 300b has the most output power, they say 8W into a 3.5k load. I use a 5.6k load for about 4~5W and it’s still plenty.
But the 300b is a hard tube to drive. So (in my opinion) it’s sound ,is more dependent on the input stage. I have tried .
FI, OK but soft.
SSRP, just couldn’t get it to work for me.
WE-91(6sj7) not bad at all, may well be many people’s cup of tea. If I had the money I’d try 310’s.
DRD,I was still on the 45 honeymoon, so not a fair trial, must get back to that.
And now the choke loaded D3a. This is working for me so far. What I am looking for may not be the "best". What I Want is a sense of life or emotion. Not something pure but clinical like a gain clone. (though I will not part with mine)

Some reviewer once said something like "the 300b sounds great but you always know you’re getting a show"

I was playing some James Cotton a wile ago and I was at the show.

On to the 2A3.

2.5 Watts.

If this is enough power for your speakers. It’s pretty much a ‘no brainer’ They are not too expensive and easier to drive. There are so many kinds out there both, new and old you can tune the sound a little

If you have high efficiency speakers, that’s what I’d do. If you have a 3-5K transformer you can try something else later…John