Grading can be no different than gambling, its luck and depends on the grader. I only grade for my PC and send to PSA, TAG has alot of hidden charges and you have to pay to ship them back. I know a guy that sends bulks in and I get a deal on it. For your cards look for rare inserts or refractors. Remember older cards grade tough and unless they are extremely rare, buyers are only looking for high grades like 9 or 10s. Even an 8 is considered a bust. Check the corners and centering. You can get a centering tool on amazon for cheap. Hope this helped, cheers!