Another record mentioned in Mosconi's book is
Best grand average, world tournament—averaged 18.34 balls per inning, Chicago, 1950
The 1950 World Championship had 12 contestants.
In that section of his book, Mosconi talks about the change from 10 foot to 9 foot tables,
However, in August of 1949, the BCA shortened the standard pool table from five by ten feet to four and a half by nine. They also widened the corner pockets from five to five and a half inches and the side pockets from four and a half to five. One reason for the change in table size was that manufacturers were producing five-by-tens only for championship play. The proprietors of pool halls had been ordering the smaller tables for years because they could fit more of them into their rooms. But essentially the changes were intended to speed play and generate excitement with the likelihood of longer runs. By way of compensation, the number of points needed to win a game was increased from 125 to 150 for national and world competition. How much of a difference did all of that make? Enough to say that starting in 1950 the game of pocket billiards was transformed; it became a markedly different game.
...
It no longer made much sense to play defense. On the one hand the shots were easier to make; on the other, it was more difficult to leave your opponent safe, for he would always be closer to the object ball than he would have been on the larger table. Almost immediately, records began to fall,
Cohen, Stanley; Mosconi, Willie. Willie's Game: An Autobiography . Open Road Media. Kindle Edition.