90% of the time, I proc a mob before it readies a tp move. And 99% of the time I kill a mob before it comes out of proc-stun (1% I have to re-up missing buffs when I proc at full health).
So dark spore is rarely an issue for me, and most of the time it's easily fixed by a cure4 from my bard. I'm a mithra as well (with hp merits) and I know I'm somewhere around 1.5k health. I always cure4 myself when I get to yellow which is somewhere around 1.1k health. For you, I guess you're sitting around 1.3k health. Thus throwing a cure4 at 1.1k health would be a pretty big waste.
I think you should change your merits. MP merits aren't very useful anymore anyway except for one ring.