If you are talking about North Amenrca then it is 25 invites per age group (without trips)Premier Zone - Junior - Senior - Masters
APAC Zone - 4 - 4 - 4
LA Zone - 2 - 2 - 2
NA Zone - 25 - 25 - 25
EU Zone - 20 - 20 - 20
So if your top 25 in your country in your age division your invited just not trip? If so... sweet!
Yes, and since Nationals is of large K-Value and such a large event in the U.S. and Mexico, there is a very good chance that 8-12 of those invites granted at Nationals result in players ranked in the T25, passing down trips to as far as #37 in NA.