Myself, if the heads are off, I'd do it now, it will never get any easier. Think about it, you're leaning over a fender, you come to the area of where the shock towers close up the space to work in, trying to keep the tap square to the hole......why make it hard on yourself. Set them down on the edge of the work bench, sit on a shop stool, they are right in front of you, easy to work on, easy to see, easy-peasy. Just a thought..............
Back in post #7, you stated you've never done stuff like this before, you were kinda nervous...........Just an other thought