Not sure about shutter size that you refer to. I've seen one of these front-mounted on an Alphax shutter; it just screwed right in.

One complication with this, which I didn't notice until now, is that I can't unscrew the front element from the barrel. The rear element comes off easily -- I don't know what the problem is, and I don't want to force it.

As I recall, I believe Dagors were originally available in Compound shutters, and another type as well that escapes me at the moment. But I don't believe that taking one from a barrel mount was a straight shot into the shutter -- I could be wrong on this....

I'd welcome any further detail on this!