Your question prompted me to correct my healing calculator as it was valuing crit too much, but I'm thinking it might help you answer your question, and will definitely allow you to play around a bit. Check it out: First off go to:
(preferably using Firefox as your browser)
Start with the Armory tab at the top, putting in your information, make sure to not forget the apostrophe. It should pull out your stats, and clears the screen a bit, only showing shaman stuff. At the lower left you should see a Shaman section, and a Settings tab in there that you can open. The first option there is Health deficit percent, it's currently 20%, meaning that I am evaluating the spells as if they are cast on targets that are at 80% health. You can adjust that to your desired percent, 50% for instance for your triage mode case.
Then on the middle of the screen you can see your spell, how much each of them heals for etc. If you hover over a spell's HPS, let's take Healing Wave as an example, then on the far right you will see a table, showing how much your hps on that spell will increase if you gain 1000 more of a stat, for example 1000 more crit will increase it by 2.3%, 1000 more int by 3.92% etc (your numbers might be slightly different if your gear has changed since I write this). The column next to that shows you the relative weights that this imposes on the stats, making spellpower count as 1. For instance 1 crit is worth 0.34 spellpower, while 1 mastery is worth 0.27 spellpower. So for healing wave, crit is better than mastery at your current gear. You can hover over each spell there to see similarly how the various stats would affect it.
Now, what you want to do probably is look at an overall "rotation", instead of just each spell separately. I have designed such a rotation for you, using a minute of fighting as a base interval, but you can adjust it as you like. To load it, open the Rotations tab near the top, Click on Import Rotation, and copy and paste the following in there:
This should create 2 tables, one on the top which has a summary of all "rotations" you've set up on it (you can create multiple rotations and compare them). The other below, with the list of spells and info on each of them, as well as totals. If you hover over the summary table's HPS of Eff. HPS values, the table on the far right should now show you how much 1000 more of a stat would affect your overall rotation.
You can see crit being at 0.29 spellpower while mastery is at 0.24 spellpower. And that's at 50% healing deficit percent. This tells me that both crit and mastery are fairly close to each other, and I would probably tend to prefer crit myself because of resurgence and ancestral awakening.
Well hope that gave you a basic idea on how to use HealCalc and if you have any problems with it just pm me or leave a post at: