Jon
IMHO the R&A and USGA agreement in May 1921 got it right with a ball of 1.62 inches (dia) and weight no more than 1.62 ounces. Then in the 1929 the USGA got it totally wrong by increasing the ball to 1.68 inches (dia) and weight of no more than 1.55 ounces – this was updated in 1932 to 1.68 inches with max. weight of 1.62 ounces. Sometime in the middle of WW2 the USGA introduced another requirement for the ball, velocity standard.
I believe that the USGA then allowed the 1.68 inch balls into all their competitions from 1968. It was about this time that the R&A in to hope of standardizing the size of the ball world wide suggested a compromise of the 1.65/1.66 inch balls, which was ignored by the USGA, resulting in the 1.68 inch ball being used in the 1974 Open. It was formally confirmed by the R&A in 1982 the 1.68 inch ball would become mandatory.
I just love a good compromise, don’t you? However I also believe that this was the start of our current problems. I sincerely believe that the USGA got it wrong and that the R&A showed its normal colours by doing absolutely nothing (as usual).
The ball debate is far from over but who has the balls to say they got it wrong. Will the R&A step up to the new challenge? Regrettable I do not believe that either party will actually do anything, leaving the architects and courses to struggle on regardless.
The Game and the poor old golfer being the looser, but then what's new?