Fruit for a summer shandy

[PaisanMaisano]

I'm looking to begin crafting a recipe for a summer shandy and I have seen several different methods of adding fruit. Most go with added fruit to secondary, some to the boil last 10 minutes or so. I've seen some that add fruit juice to the keg. What are some of the benefits of each?? I'm thinking lemon, orange, pineapple, or even berry. If anyone is adding fruit juice to the keg, how much are you adding?? And the million dollar question is how much will adding fruit change the FG?? Any thoughts, much appreciated!

- Paisan