Is it possible that Pilkingtons jig is for the bonded, rather than the smaller (VX/ie) rubber seal screen? Not that this helps?
You know, I hadn't thought of that little detail at all...
If the screens are actually a different size, and you'd certainly assume they would be, then they must have two jigs.
It would be very interesting to know if the other jig is still accurate. I say interesting, maybe a moot point though, as where on earth would you get a rubber? There weren't any available back in 2011.
Andrew.