Salopian,
As I'm sure you have done already, a Google search shows T. W. Menck's Ralston, Nebraska shop permanently closed.
I have one of his 2- Bit adjustable firing pin bushing tools as he calls them & it works well & is made to use a 1/2" socket. His instructions suggest using an impact driver but I've not found that necessary (yet).
He has a good drawing of his tool in his instructions & failing your locating one somewhere it does not look like it would be too difficult for someone with a lathe to make one.
I'm not good at posting photos but if you want to PM me with your E-Mail address I'll scan the instructions & send them to you.
Nothing wrong with the Cole design either but on a gun that has been fired much you will want something more than a slick handle to provide some torque.
Those striker disc tools that have a handle that looks like a chamber brush handle are most useful as case accessories but I imagine you already know this.
