This is going to require a bit more work than I can do remotely at work since I am firewalled. Probably will try getting this done later this weekend.
Here is what I am planning on doing.
Creating myself a fake toon using the WoWhead tool (http://www.wowhead.com/list
and reforging like I Normally do using Full T15 gear, minus 2 pieces that will be upgraded to T16 (to give the bonus) using the stat results into HealCalc
Int, Spi, Crit, Haste, Mastery, Weapon SpellpowerT15 Assumptions
Then create two Rotations using assuming Chakra: Sanctuary.
First Rotation, assuming no DI: POH, Sanctuary (on CD), POM (on CD), COH (on CD) for a 2 min period.
Second Rotation, assuming DI, the same as above but adding an additional 4 POMs for Divine Insight.
Then I will replace 2 other T15 items on the wowhead tool to grant me a 4pc T16, and the increased stats, but lose 2pc T15. Rerun the same rotations. Key in those new stats into HealCalc... rerun the rotations.
Assumes Sanctuary's ticks are fully consumed for the whole duration. Assumes all POM casts, are done on CD, and each charge is eaten before the CD is complete.
Then we can run it again for different tiers of gear. In the end we can get a result. This should let us see the net impact of the set bonus and the impact of the stat increases.