Rebbi,
You do not need to roll the tubes, it sounds really great stock. You misunderstood the discussion. I enjoy rolling tubes to tweak the sound to my preferences. In fact, as it turns out, I believe I now prefer the sound of the stock Shuguang EL34B slightly better than the NOS RFT Siemens I recently purchased at a cost of $200 for the Dynamo based on Tim Smith's 6 Moons review. If you read Tim's review he used the Siemens, SED Winged C, Psvane Black Treasure, as well as the stock tube; he settled on the Siemens. That of course was to his ears in his space, with his ancillary equipment. In my space with my ears and my ancillary equipment, I think now after listening that the stock tube (again, my space) sounds more open, airy, better separation between instruments, easier to discern what is where, provides a bigger, stage. The RFT Siemens is a bit richer and warmer still, deeper bass, yet not better, just different. Both tubes exhibit wonderful tone, excellent harmonics, dynamics, stage and so forth. The Dynamo will play everything you throw at it in a natural and organic way, it is a musical amp, neither too Yin or Yang, but just right. I have a matched pair of Black Treasure 6CA7s on the way from Grant Fidelity, but you don't have to do what I am doing, comparing and contrasting tubes. The Dynamo sounds great as is.
To answer your other question the volume control is not a problem for me, likely not for you. I'm only going to play CDs on this amp, so no problem with additional inputs.