Thing is that youre doing normal modes. You can heal normal modes in 350-355 average gear without any issues now (I just did it on my hpally). When youre in full BiS normal gear, youre not going to need *any* spirit for normal modes lol.
As for OP's question - can't really comment much with shard, but seeing as we're on the topic here, I am interested in how druids *without* the shard are doing in heroic firelands currently. I'm running with 2x 391 (domo/alys) trinkets atm, with around 2.7K spirit in our 25 man heroic alt run (not touching rag on alts) - I don't particularly have mana issues on anything but Rhyolith (usually bleed myself dry so I have to drink a mana potion for tranq during P2), and Beth'tilac if the second phase starts dragging out.
Seeing this, I'm interested in what other people seems to make work, spirit-wise, without the shard. I've considered dropping spirit, but it seems like it would hurt us when we are doing Beth/Rhyolith, as I'd run OOM even sooner on those. Admittedly, I usually don't use lifebloom covering during ToL at all, and I should probably look into how that works (1 lifebloom on each person, or stack them?) to regen some mana, I guess.