Beckett Message Boards

Hi, I'm new to the grading process, and I'm sure this comes up often, but I would be grateful to anyone who can give me advice on the topic. I recently acquired a complete 1984 topps tiffany set, and I want to have the Don Mattingly and Darryl Strawberry cards graded, but I don't know what to enter for declared value. Is it simply the beckett price value or is it different? You see all of these increase the cost of the process--getting the beckett price costs money, and the higher the declared value, the higher the cost. I want to keep the cost down so that it doesn't erase the benefit of having the cards graded in the first place. I expect both cards will be a 9...what value should I enter?

Also, I picked Mattingly and Strawberry because I'm assuming that they will be the most valuable...does anyone suggest any other cards from that set that would be worth having graded?

Thanks!