Depending on how stiff the cable is, I'm thinking it could work well to leave a couple inches and tuck it through the light bracket for later use.
But I must say that full dyno lighting has been a game changer for me. It's nice to just grab a bike and have light whenever the wheels are turning. And after being a bit concerned about the standlight on a dyno taillight, I was really impressed by how soon it took a charge and lasted while stopped.
Pretty inexpensive to try, too.
