Hi,

So ... let's resume.

IF those 3 wonderful servos are " so good " ... why not test their behaviour into the skull, with a so simple 555 based servo driver ( 10 components is a maximum ) that will produce neat-known signals ...

here is one of them:
http://www.hvlabs.com/555servo.html

would certainly save time to everyone and, may be money to you ...

Alain