I know that you are good with maths and formulae, so I would like to ask you the formulae for calculating the size of miss that relates to degree the putter face is out of square at impact.
Larry Stanley in his website gives two examples, a one degree error missing by 2 and a half inches at the hole 10 feet away, and missing by 5 inches when the hole is 20 feet away.
Bernard Langer in his book Langer on Putting states" The square clubface is essential. To repeat, if your clubface is 1 degree out at impact, it means the ball is 1 and a quarter inches off line on a 6-foot putt".
Incidently I found the book a good read with Langer being insightful in his observations.