Here's the team that I used to destroy Omega Shenron:
Plus Omega Shenron friend. I am debating swapping out STR Beerus for STR SSj Goku (GT), but Beerus links with Omega for +2 ki and +15%, and Omega is always linked with Pan anyways, so I don't need that GT link. I keep Omega and Pan together on a turn and Super Gogeta and SSj3 Vegeta on the other turn, with the other 3 rotating in the third slot. Only used one ki changing item to speed things up!
Edit: My post brings up a fantastic tip that I don't think made its way into the OP: Once the battle starts, you can manipulate the order that people attack in. The left and center slots will attack alternating turns and the third slot will attack every third turn. So, if you want to keep two cards together all the time, keep them in the first two slots. Here's a kind of diagram if it makes it easier to see:
Turn 1: 1 - 2 - 3
Turn 2: 4 - 5 - 6
Turn 3: 1 - 2 - 7
Turn 4: 4 - 5 - 3
Turn 5: 1 - 2 - 6
Turn 6: 4 - 5 - 7
The order at the start of a battle is random, though, so I usually use the first phase of a boss (The PHY Omega Shenron, etc.) to set up my order before I move on to the next phase. You order lasts until you go back to the map, so once you set up the order of your cards, it will stay that way through every phase of a multi-part battle like Super Vegito, Super Gogeta, Omega Shenron, Buuhan, Gotenks, etc., making those battles much easier.