Here is the information Vixsin gave in the other thread about the resto 4 pce.
So, on average, you're looking at maybe 30-35% the throughput of your source heals (remembering that things like Restorative Mists, AG, totems, hots, HR, etc. will not be duplicated). In the log above, using HS spam for the duration, the Spirit Champ did 316,641 raw healing, which translated to 0.6% of the Shaman's raw throughput over a 4-minute encounter. Even being generous and assuming 1% effective per usage, and that the shaman used the bonus twice within the timeframe, 2% bonus healing is is still a very low contribution for a final tier bonus.
[00:07:44.387] Restac Healing Surge Restac +23418 (O: 0, O: 59631)
[00:07:45.162] Spirit Champion Healing Surge Snuglz +*26320* (O: 0, O: 35981) = ~38% of source (but the duplicate can crit so it did 2x)
[00:07:45.597] Restac Healing Surge Restac +*0* (O: 0, O: 165544)
[00:07:46.364] Spirit Champion Healing Surge Cyus +*19803* (O: 0, O: 33849) = ~32% of source
[00:07:46.892] Restac Healing Surge Restac +*0* (O: 0, O: 165206)
[00:07:47.564] Spirit Champion Healing Surge Emmawatson +*41580* (O: 0, O: 15884) = ~35% of source
[00:07:49.575] Restac Healing Surge Partyhats +0 (O: 0, O: 82359)
[00:07:50.399] Spirit Champion Healing Surge Bubbleszz +28894 (O: 0) = ~35% of source
For me personally, this means I'm not going to prioritize 4pc. I'd rather see our teammates on the Prot token put it to better use than claim 1-2% EHPS is essential to my own performance. (Now, if this gets changed and we start seeing Spirit Bros duplicating the entire heal, you can bet your arse that 4pc will be on my shopping list).