I am personally against retaking the SAT practice tests, my reason is that the SAT questions lose their difficulty if you have seen them before. I think the best strategy is to take practice tests, review them, internalize your mistakes and what you learned and move on to fresh practice tests. There are actually plenty of official SAT tests out there. You can get another 10 tests from Collegeboard’s Official SAT Online course: http://www.amazon.com/exec/obidos/ASIN/145730001X/st06202-20
Other than that there are additional practice tests that Collegeboard has released over the years. I assembled the links in this post: http://talk.collegeconfidential.com/sat-preparation/1277787-links-to-additional-official-sat-practice-tests-from-collegeboard-p1.html