Have you tried Lite Steam A Seam 2? That's what I've been using for portrait quilts and it's working very well. I like that I can just finger press it and it stays on, but is easily removable if needed. I just stick my fabric on it and then cut both at once and then peel the paper off and place the piece. All pieces can be placed and moved until it's time to press them on permanently before stitching.
I think I'll stick to a small zig zag as I like the look of the stitches and my time is very limited. But who knows, I haven't started doing anything yet!