2015 Topps Super Bowl Legends Joe Montana 1/1 autograph

[dennishuber1]

I'm thinking of getting the card named in this thread graded. Is PSA or BGS the best way? Which one would add the most value to the card once it's graded? I've never got anything graded & am confused by how to insure the card as the instructions say to insure based on the cards value. However, there's no value listed for the card. I'd appreciate feedback on how to proceed.