As far as i know the detent won't be a problem. the cocker is closed bolt marker so if you're using the eblade in semi mode it will be perfect. the problem occurs mainly on open bolt guns where the breech is open when its at rest, that way the halo has loads of time to push the ball past the detent (if you're only shooting the occasional shot), whereas the cocker chambers the ball and closes the breech, meaning that theres only the split second when the breech is open to allow double feeding. If you've got the eye working on it then it will close as soon as it detects that ball and so wont allow enough time for the halo to double feed.
as for the second bit of your question angels seem to be fairly sensitive as far as halos go (at least in my experience of them). eclipse fangz detents are a big no no as well as far as halos are concerened, they're just not stiff enough.