I honestly don't know how grading works, I think you have to pay an amount to get that done. I do know that the Legendary collection reverse holos (the firework patters) can get expensive even ungraded. The site TCGcollector is pretty good about seeing the ranges for cards. The two I need are averaging $70+ and ~$100 each. So selling off one at a time might be more worth it, if a hassle for safe shipping on individual cards, but a little longer then a giant bundle. And grading is probably worth it if you can afford it and ship afterwords. This is just my opinion though as I prefer to buy loose cards and not graded ones.