In the product page, it mentioned that the output power depends on the choice of tube.

So would 6L6 output higher than 6V6? If yes, what is the % higher.

If I want more dynamic and better bass for classical music, what tube should I choose?

hi, I just discovered a combination of tubes that sounds particularly punchy and bassy, excellent for anything in general i would say, not only classical music. And nothing was lost, neither detail nor focus. Here goes:nos rca 0d3 regulator, reissue Genalex 6v6, nos mullard 12at7, nos philips 6x4 and 'stock' remaining rectifier, I forget what type it is, oc3 or something. The 0d3 glow violet, while the rest of the tubes glow orange! But of course, the sound is what matters and it is fantastic. I have just listened to Leonard Cohen's Various Positions at barely audible volume (neighbours) and I could hear every little bass note, including the growl and the attack and the little swish of the finger on the strings. Ok, maybe not the swish.
But all the rest.

I had tried an 0a3 and a nos  westinghouse 0b3 and they did not have any desirable outcome.