One facehugger per shoot goes by fast!  Happily, cardboard stands up to birdshot / target loads quite well.

A field-expedient way to get the most out of every Facehugger is to bring some duct tape.  Taping a clay pigeon onto the back of Facehuggers actually works decently, and helps get the most out of each one.

Duct tape also helps if the Egg eventually comes away from the steel plate in the field.