That is just GREAT!!!
Personally, I think any boiler that will drive that beam at a nice slow steady pace is the right boiler for it. I think a Beam Engine should look Sedate while it is running, rather than hectic or frantic like is so often seen!
Lovely engine, and yes, they are rather heavy beasts!
The classical combo mate for that engine would probably be one of the Stuart 500 series boilers.