Glad to see you dropping more knowledge here! From the American side it looks like top 12 players in the US were invited ages 11-14. So 35 total players invited to 1999 TMB Hawaii Finals makes sense.
www.elitefourum.com/t/wotc-chat-logs-from-feb-2000-to-nov-2000-q-a-w-employees/16872/1