I think it would depend on a few things. If you're only considering slotting at level 50, that opens up SHOs and possibly purples as options. Otherwise it'll probably be just franken-slotting regular sets.
You can probably get pretty high on the three things you mentioned if you ignore recharge and end redux. The power has a longish recharge and a high end cost though, so unless the rest of the build compensates, ignoring those might not be your best option.
Trying to balance all those things I can usually manage to get 50%-60% on healing and damage while also getting good recharge and end redux. If I try to push one of those things much higher the other gets hit pretty hard.
Was wondering if anyone could make a good suggestion for IO slotting in life drain? Was hoping to maximize damage, acc, and healing if possible. Thanks!