It's a Webley type with the guard around the top. I used a 3L 300Bar at a meet once and scared myself with it. I'm not sure I'd give one house room - they're a bit mad.
At the time, my bottle valve at home wasn't restricted like my new one is, but what a surprise.
Change your underpants and work out a way of controlling the rotation of the valve knob more slowly. I found it awkward to reach into the guard area to do that, but I'm sure you could find something to fit onto it. A coaster is a good thing to try cheaply, but I was thinking more like a socket or a sink spanner that gives some height too.
If you just can't control it, but want to keep it, you could get a new, restricted valve from MDE or wherever.
You're very brave.