You will have to ask in a way that is indirect.
i.e. "I am thinking about a buying a new line but I am wondering what provisions you make to lower the pressure in the extruder because I am running very viscous resins, do the channels affect it & Has there been any advance in design over the last 20 years and what did you supply in the past?" and "are my new lines designed the same way as the older lines".
It is more of a sales question and you have a right to know if they intend to sell you more! They do not have to divulge technical info like the nominal value of the channel just is there a difference. Then we know we just have to go to a newer model when we scale up.
Anyway in the document describes what I mean. I know the lip gap is okay so I don’t care about that so much- I care more about things that restrict the pressure from the extruder getting to the lip. The head can be restrictive (not the lip THE HEAD!). See in the powerpoint attached how the head works, the length and diameter of the channels determine how the pressure gets to the lip!
Please ask more questions if you don’t understand?