You do not need your healer to stay in tank quad, they should spawn blood as well, blue heals last longer than the 10 seconds he will be away from the tanks, so they will not be without them. But apart from that there is no reason your tactic won't work, just need execution.
edit: if your clickers are dying, you can go an 8, 8, 4, 4 setup it's a little tougher on the tanks, but then your clickers can stay in that quadrant for the 1 min it takes to the snare etc to wear off, effectively giving you a 7, 7, 5, 5 setup which is also very safe