mouth placement "heads"?

Hello. I am currently teaching English to both children and adults in Japan. Like most teachers in the same position, I'm having trouble with some of the sounds. I've got "L" down with all of them, but some others are giving me trouble. "Th" and "V" at the moment. Getting a true h-sound is interesting, too. (Before coming here, everyone I talked to that Japanese uses H and not F, but that that's a lie, in my opinion. It's sort of a special cross between the two. But that's beside the point. )

Anyway, my adult students are quite dedicated, and want to learn, and for a class like that I don't mind getting technical. A few friends have suggested I get the tongue/lip placement diagrams (they called them "severed heads") and use those. I'm willing to follow that advice.

The problem is, I can't find the diagrams anywhere. I've tried every word combination I can think of in Google and Amazon.co.jp.  I don't mind paying for them if they're copyrighted and that's why they aren't available o/l (although I'd bet money that they're out there and I just can't find them), but the internet would certainly be preferable. 

Does anyone know of a website where I can find them? I'd prefer diagrams where each one had a single sound, rather then all the sounds in one head with complicated arrows and whatnot.

Thanks in advance,

Seven