The skin-yankers are turning out to be easier than I thought. There's been glitches - the lines seemed to be firmly attached to the 'skin', but some of them popped off unexpectedly. Not because of the tension from pulling them, but because I bent them the wrong way, and the Krazy glue seemed to have cracked.
But the principle works. Here's how kids! The forehead lines run upwards (the direction they need to be pulled in), through little holes, and to bolts at the top. The bolts are inside nuts (expoxied to the shell). The lines will be pulled by winding them up on the bolts. They're allen-key bolts, and will be accessed through the top of the hat. Gonna be a trap door up there.