You know, removing that coolant over flow tank would give you the room you need from the top.
On elbows..yeah I rtvd them. The first set I put in I didn't use any and they leaked within 6 months. Just my luck though, as a first time installer maybe I didn't do it well enough. Idk. Ive done more than a few by now, I rtv them only because it can't hurt. I dont want any comebacks.