I still am not providing a numeric value for mana tide regen for other healers. I can't see how that would be quantifiable, and I'm not sure it would even be useful. If your other healers need more mana to do their jobs, that's something to consider subjectively against personal benefits.
You have a value on your sheet for personal spirit. That presence would indicate that (a) you saw how it was quantifiable, and ( you thought that quantifying it was useful. If every other healer in your raid did the same, you would have a reasonable estimate for the value of MTT spirit to your raid. It's not a simple problem, but it's far from being intractable. Certainly we need not throw our hands in the air by claiming the issue is "subjective."
At the very least, it's useful in a tool of this nature to have a knob to turn to see how varying the raid's value for spirit affects the relative ordering of the trinkets. While one may not agree with my approximation of "each other raid healer values spirit the same as I do", which is certainly fair since I'm not sure I agree with it myself, I think you would likely agree with my tool's placement of DMC:T and Mandala above e.g. Tyrande's Favorite Doll for 25-man raids.
The power of MTT in raids is in its ability to provide mana to other healers, certainly that factor is more significant and therefore more deserving of examination than simply quantifying the self-return.