My Cuban League project has five main sources of evidence:

1) 101 games played between major league teams and Cuban League teams, 1908-1913 (and the major league records of players on those teams).

2) Major league records of Cuban players during these years (primarily Armando Marsans and Rafael Almeida).

3) Exhibition series played between black North American teams and Cuban teams, 1904-1912.

4) Regular Cuban League seasons, 1904-1914.

5) Various exhibition games, special tournaments, and other leagues involving Cuban teams, 1904-1914 (e.g., the “Premio de verano,” or summer league, of 1904).

There may be as many as 3,000 (or more) plate appearances by major-league hitters against Cuban teams during this time, including Cuban players who appeared in the majors and one major-league player, Matty McIntyre, who played in the Cuban League (in 1912).

My sources for Cuban statistics are two Havana newspapers, La Lucha and Diario de la Marina, which together covered pretty much everything during this period (though I only have access to Diario through 1907 or 1908). When I’ve finished gathering the above data, I’ll create MLEs by comparing the major leaguers’ performance against Cuban opponents to the Cubans’ performance in their own league.

This is historically very important, not only for assessing the abilities of Cuban players relative to the North American leagues, but also because statistics are especially rare for black U.S. players before the founding of the Negro National League in 1920. This means that the Cuban newspapers contain precious evidence of the abilities of men like Pete Hill, John Henry Lloyd, Rube Foster, Grant (Home Run) Johnson, and others whose careers are too often relegated to the realms of anecdote or myth.

Since I’m planning to write up this study as a lengthy article or possibly even a short book, I probably won’t post exhaustive statistics from it here. But I will put up occasional lists or tables to whet your appetite.

BTW: The “Cuban League” had various names at various times; often during the early twentieth century it was referred to as the “Campeonato Nacional,” or the Havana League, or some other name; English-language sources usually call it the Cuban Winter League, which was never its official name (at least during the periods I’m familiar with). I tend to follow René González Echevarría, who, in The Pride of Havana (the best book in English about Cuban baseball), refers to it as simply the Cuban League.

Also, see this great site on Cuban baseball, and this forum for some pretty lively discussion of international baseball in general.