There shouldn't be this big of an issue with mana for white mages. What content are you running into this problem with?
Thin Air + Lucid Dreaming easily cover DPS and a few raises if used wisely. Rely on your oGCD heals first. The 71 dungeon can be rough if the tank is fully pulling (first pulls feel rougher on WHM due to how slow lillies appear).
What's concerning to me is you talk about not wanting to DPS at all but your biggest AoE damage at that level, Holy, is also a huge source of damage mitigation. If you're not using it, or DPSing at all, of course pulls will both take longer and be far more dangerous. Using your mana management tools in conjunction with it will get you through the bigger pools as long as the tank is doing their job too.