Provide one solid reason why Rapid Rejuvenation is optional for 10 mans over Swiftmend or Innervate. There is absolutely no reason not to be using it when raid coverage is no longer a concern. One reason why you might be having mana issues is your heavy use of Regrowth. Nourish costs 18% base mana while Regrowth is 29%. I would pay closer attention to your meters at the actual overhealing done by Regrowth and that could prove exactly how useful (or useless) the glyph is. You could be burning through a lot of mana that's just going into overhealing done.
Turning to 10 mans i usually run with Noursh, swiftmend, and innervate. 2 healing alot of ICC 10 content you will want the ability to effectivly heal your tanks when the time is needed.. Healing tanks + raid will usually consume alot of mana (especially since you only have 2 healers) and so glyph of innervate again.