Chimney capping and flaunching

[tren]

Hi

I have this chimney made of granite stone on the barn conversion I am working on.

The flaunch is was poorly done (just a bit of old concrete which lets water in) so I need to redo it properly but I would also like to add some capping.

Any suggestion? I need a solution that can be done by one person and off a platform.

I was thinking building a concrete capping+flaunch by building a wooden frame around and above the chimney stack to pour some concrete in (such as attached). I have seen that technique is fairly common. Is that a good idea?

Thanks!