Surely you can get manufacturer and specification by using the Type Approval number that will be in the corner of the screen you will get fitted? (it might not be free though; I'm sure there's 'libraries' out there)
Windscreens are part of type approval; I've dealt with OEM windscreens approval and different layers/material might result in additional tests; so imagine the same is true with non-OEM screens.
Admittedly the tests are affected by heat transfer (de-frost/de-mist) so anything other than that might not be up to scratch, hence why people seem to have issues with heating elements/sensors etc.
I was apprehensive about a non-OEM screen being fitted to my Z4, but the wiper sensor was part of the rear view mirror assembly, and the screen just had a little clip for it to clip on and then just a hole where the tint was missing for the sensor to look out of.
I can imagine that if you have electronics in the windscreen it might cause issues going for non-OEM, as it's not something they have to test for.