I am offering my 12 years experience as an educator and 18 years experience as an IT consultant to help a group of high quality students achieve something in life.

A group of high quality students? Don't make me laugh! It would be more accurate to say that that group comprises students from wealthy families. That does not necessarily equate with high levels of either knowledge or ability.
I should add that the preliminary test results are of no consequence in some cases. As a teacher, you can end up with low quality students in front of you. The school director will likely place them there to make money! Probably, he (or she) will have already promised their parents to use his (or her) clout to get their offspring places at venerable Western universities irrespective of GAC assessments!
There are many negative posts already about GAC/ACT on the net, some of which have been submitted by whistleblowers. I myself have experienced firsthand the dirty tricks that go on at a GAC center in China. You're fooling no-one with your words of praise for your 'Exchange School'.