AJP Head thickness

[Jhonno]

Not got an response in the Cerbera forum, so was pointed to ask here..

How/where do I measure an AJP head to work out if, or how much it has currently been skimmed? What is the standard thickness?

[Jhonno]

Cheers gents.. I always feel a bit bad ringing specialist just for advice. I try to buy something off them at the same time!