You're doing pretty much what I do, and I personally have no intention of re-speccing for this - I just learned not to rely on a heal.

My pally is fully prot specced, VERY poorly geared (far, far worse than yours) and doesn't have the trinket (or any passive healing at all, in fact). I do have a couple of trinkets that improve dodge / block, and I alternate those.

I keep him alive by actively balancing seals of light and wisdom and bubbling up to heal when he gets below 1k health. If I get below 3k health and it doesn't look like my bubble's going to be available when I need it, I jump down.

Once I got the balance right, I *always* end up resetting Zolo after 10-15 minutes to prevent him dying, rather than my pally