I've just figured out that these cans actually sound best with zero gain on my BCL Linear, but the knob turned up to 3 o'clock or so. For a long time I thought they needed high gain and low volume to sound best, but then realized that I was getting a bit of harshness and also a weird tingle in my right ear. I think this is a much better option.
I don't fully understand the whole gain issue, but I have found that weirdly these cans don't need a lot of gain, but they do need power (which is also volume). Someone better at this stuff can help me out here, but this is actually probably an explanation for why I think the original Schitt magni was also fine (even if not ideal) with these cans--a lot of power with no gain.
So, in case anyone is looking: if you can actually find a pair of these, and get a high-powered cheap tube amp or Schiit magni/equivalent amp, you can have an amazing for acoustic classical, jazz and rock music, as well as female vocals, set up for under three hundred Euros.
I think the next step up from there would be an entry-level Stax set-up.