Use the rubber band to secure the hook to the crab. You can vary the
orientation of the hook, depending on the type of presentation you are trying
to achieve.
Instead of using a popper after dark, try using a slider. Its sort of like a
pencil popper with the small end towards the eye of the hook. Generally you
work it slow with a hand over hand retrieve. It creates a ripple on the
surface not unlike a slowly worked Redfin. Don't strike at the splash, wait
until you feel the hit (easier said than done sometimes). George Roberts
detailed how to make one out of lobster pot buoy foam in a recent publication.
Lou Tabory's Surf Board Slider also works well, as does his snake fly with
a heavily dressed deer hair head.