I use a total of 13 buttons only for healing. Shield and Flash Heal on all clones. Shield, Greater Heal and Renew for tank, and Prayer of Healing. Also a 5x Gift of the Naaru button. It takes some time getting used to but it's definitely worth it for PVE. I'd assume the same for PVP. The trick is to find a good balance between complexity and efficiency. Don't use more than you can effectively micro. Start with ie 1 button pr character, and add more as you get comfortable.