What could he practice on that's easily obtainable? Anything? I know students practice stitching on orange peels sometimes but a peel isn't really big enough to be an analogue of a whole head. Any ideas on what he could use to replicate the chip compartment?
Googling "Human head analogue" and "Human scalp skull analogue" doesn't help at all.
ETA : This is set before Judgment Day. Pigs are still kinda hard for a regular suburban teenager trying to live underneath the radar to come across though. ;)