It doesn't matter if you take the SAT or ACT through a talent search or just on your own - you sign up for the test the same way. My understanding is that the ACT scores remain on your account regardless of when you took the exam. There are discussions on this on College Confidential. Some colleges request you send all scores when you apply. I think that they really don't want your 7th grade ACT score, and since ACT scores are sent individually by test date, I don't think the college would even know that you took them in middle school but didn't send them.
As for prepping for the CR section, I would recommend looking at Erica Meltzer's thecriticalreader.com There are some helpful blog posts there. She also has written a book on the Critical Reading section where she discusses the nuances of the passage based questions.
While I always found the verbal section to have some fuzzy questions/answers, I can now see that there is a way to approach the questions (after reading some of the blog posts). With all due respect, I really don't think that the questions are somehow geared toward NT folks. I think it is a matter of paying attention to the precise wording of the question. That and some kids just seem to understand how the test writers think.
