after cutting (Full Skull Mount) the hole in the brain cavity should be big enough to fit a small square peice of wood in it, push some news paper into the cavity and fill with car body filler, the news paper is to limit the amount of filler needed, then insert the wood into the body filler, leaving the wood flush with the cut, fill in the gaps and leave to set, half way down the skull (underside)drill a hole and put in a wall plug, if plug is not tight enough put some body filler around the plug with a small modelling tool. when dry about 10 mins put a screw into the wood and the plug and screw in slightly cut the screw head off with grider at an angle or so it is pointed leaving 8 to 10mm of thread sticking out.place on sheild in desired place and press on skull so you make two small marks on sheild where holes for new screws are to be located, remove the screws you cut with mole grips. drill holes in sheild and counter sink. then simply put screws through the holes and locate the screw holes that were made by the screws you took out and tighten them up.
Job Done 15 mins including drying time