I used my hotwire instrument for all of the cutting of my candy pieces. If you don't have one, it will be difficult to follow this instructable. I published how to make one some time ago. See:https://www.instructables.com/id/Making-The-Mighty-Goliath-
I didn't measure anything, just cut the styrofoam to the shape and sizes I wanted, used a little sandpaper but not a lot. It's easier and cleaner just to use the hotwire to round off edges as you go. The glue gun adds the realism of "poured" chocolate. Some acrylic paint and varnish and that's about it.