@Samantha I’ve received the sample from William Gee today. It’s the same weight as their dot and cross and I’ve just compared by trying to read a newspaper through them both. The dot and cross, couldn’t see anything through, the tracing paper, yes you can, but need to smooth over as you’re doing so. On pattern pieces, the d&c you can just about see, but the tracing paper the lines are clearly visible. It’s slightly thicker than Burda paper, which in turn is slightly thicker than pattern paper.
If you pattern fit it is the same as working with dot and cross. For storing, I use plastic folders and store in a loose leaf binder, it won’t fold down as much as Burda paper, so will be a bit bulkier.
It looks a little like good quality vellum (paper not goat skin!)writing paper, but shiny on one side and matt on the other.
If my calculations are right, it works out cheaper than buying Burda paper.