Stock MAF sensor calibrations

[MikeA]

How can I find out calibrations for stock MAF sensors? I've traulled the net for information but all I get is people with flashing MIL lights!

It's on a 1.8 Zetec. Also, it has a built in air temp sensor. Normally I'd calibrate that against a thermometer or something similar. How can it be done when its built into the MAF unit?