Effective cutting of PET

I am working on a prototype project that involves using PET sheet. I was
wondering if any of you have any real life experience cutting PET sheet
with a steel rule die. If so, what was the maximum sheet thickness you
could cut? The part I am working on is about .025"-.030" thick and I
wish to make a number of slits in it about 2" long. I don't wish to
remove any material along the slit, just "score" the sheet (I do need
the die knife to penetrate all the way through the PET). If any of you
can give me any first hand info, I'd be appreciate it immensely.
Thanks
Greg Postma