Rules for organizing, conducting, and participating in online Heroes of Might and Magic III tournaments.

Will the tournament rating provide a fair determination of rankings? Is it better than the seasonal one?

There's nothing to compare with the seasonal rating. It will take into account the results of tournaments and tournament activity, and on all resources. In the seasonal rating, even our tournament players from World of Xeen don't all participate, not to mention those who have just come from other resources...
Of course, such a rating cannot be an absolute measure of skill. But it will be more objective. And choosing one out of several with an equal number of points is unfair in any case. But in the end, we're not playing for a cow, and it's not just one tournament...

Chronologically, it can be limited, but I think it's better to give a longer period. For example, starting from the founding of HeroesWorld.