Thx for asking!
First i think we should make some change. I find two pretty good ways of doing that.
Now we handle this issue by specifying specific types. If i understand correct we have two brands to choose from. If there are some other cloth that we want to make available we could just put it in next to the others.
The other way is to make max and min of the three parameters. Thickness/wheight, x denier warp and x denier fill yarns.
If we skip to limit the denier we increase the risk of change how the sails are made in the future. Maybe the sails are good as they are.
Rafael make o good point