I have a few questions regarding this:
First
Does their shield stack, will several guardians disperse damage better then one or is only one effective at one time inside the same space.One takes 33% of the damage done inside the buble, do 3 of them take 99% or all of the damage? can anyone say or assume how is this calculated, is there some law of diminishing returns,like 1 absorbs 33%, 2 absorb 50%, 3 absorb 60% etc. Is there some kind of breaking point or a limit?
Basically if i have 5 of them is it better to turn them all at once or only 1,2 or 3 at one time?

From what i can see you can not get 100% protection, but im not sure of that.

Second
How good are they really? I mean they dont regenerate shield or hull like TEC and vasari repair craft, they just help spread damage out on them selfs a bit, so assume they are good when someone is focusing your ships but they dont generate new points of shields or hull like TEC or vasari does. Personally i dont like them much, one more reason is that they need to stand still to channel the shield. I think that instead of them you can get some more cannon fodder and firepower.

Anyone agree or disagree, state reasons please and real combat expirience and examples are welcome.