I have 2 Great Balls I have yet to claim. 1 as a reffing reward (here), and 1 as a free gift in the X-Mas Tree (here). As the ball in the Tree is specifically for Ayeun's trips, I've PM'd her and asked if she'll take me up.

I'll be taking Hanzo (Gallade (m) @Steadfast) and Tesla (Shiny Manectric (m) @Static) with me, and going to the Skyline Terrace.