John certainly seems to know what he is doing so I would be fairly confident just on the face of it, though you are wise to meet with him and discuss in more detail – and of course try it out yourself. The fact that he uses Camac levers is a plus as is the vacuum molded round back box. I prefer that box design for a harp such as the Camlan as it is light, very strong, and has excellent acoustics. It is what I use on my own harps for my own use.
The Ravennas have a different approach which is described on Dusty Strings’ website. Those are good harps too of course.
When you meet with John you might discuss hiring the harp for a while rather than purchasing it immediately. He offers what in the US it is called “rent to own” and that is a good way to go. His description is pretty standard in the industry.
Biagio