The point of my earlier reply re the Units was, while the design concept is still very valid, the rules changes and performance gains in the years since McGraw made those units. The rules regarding button size have changes, for one. Flying wire sizes and pull tests have gone up bunches etc. So, treat these antiques as they are, antiques.
The Units currently made in the NorthWest are updated for current conditions. And they work very well.
Glad you read the article.
Luke