FWIW, the only way to build a coil wrong.... Is when the resulting coil doesn't work.
I prefer a loose twist of say a 2mm-3mm pitch over parallel or a tight twist. I don't do fancy, but I do prefer the flavor of twisted wire over single strand. BUT, single strand gives me a little more time between rewicking sessions. So, for me single strand vs twisted wire comes down to... When do I want to service the atty next. In my drippers I tend to do twisted wire. On my Kayfuns and tube mech I tend to do single strand. Reason it's easier to service the drippers than it is the tanks.