I use the mapping pins, much shorter pin. They are good for various effects, such as stone balls on top of gate pillars. They push in very easily into foam board, though I always secure them with a spot of wood glue. The cast lines are a pain to remove, but you can make a feature of them, e.g. when I made some into wall mounted security cameras the cast line made it very easily to paint one half as a base & the other as a perspex cover. I have never had a problem getting paint to adhere, but worth cleaning them first.