Which edition of rankings is used for which purpose on Grand Slam tournaments?

Question

Rankings are used for several purposes:

• Players in entry list for main draw and for qualification are ordered based on ranking. In entry list a cut-off is made to decide which players go directly into main draw.
• Seeding in qualification is based on ranking.
• Seeding in the actual tournament is based on ranking.

(See also How do tennis players get into tournaments?)

Qualifying starts earlier than main tournament. Players sign in for a tournament even earlier. It seems that different version of rankings are used for these purposes.

For example, this years French Open starts on May 24. I do not have any official source, but I have read on some fora that ranking from April 13 were used for the entry list, ranking from May 11 are used for deciding seeds in qualifying and rankings from May 18 are going to be used to decide seeded players in the main draw.

Are there some general rules which decide which edition of rankings is used for which purposes? For example, is the ranking for entry list always the ranking 6 weeks before the tournament? Is the ranking used to decide seeds always the ranking one week before the tournament?

Maybe there are some differences between Grand Slams, ATP Tournaments, WTA Tournaments and lover level competitions. Therefore I am asking mainly about Grand Slams. (But it would be also interesting to know whether rules for other tournaments are similar.)

Answer 1

I'm not aware of a directly temporal relationship between ranking lists and Grand Slam tournaments (though the one week prior to determine main draw seeding is always done). At Wimbledon, too, there's a different ranking set used: for the top-32 players as of a week before the tournament starting, you then add 100% of the points accumulated at grass court tournaments played over the past calendar year, and then 75% of the best grass court result two years prior.