I'd go, generally, Kabuto > Ino > Sakura > Karin > Tsunade > Shizune in terms of usefulness for my main (Scarlet) and personal style, but it depends - Ino doesn't do a whole ton of healing and she only combos with fire as far as I'm aware, so she'd be bottom of the list for earth... But, if there's one thing I suggest - Earth's weakpoint is debuffs, so use debuff clearers. Here Sakura is really good.