There are a few ways to measure edge thickness, but heres the simplest: in a cross section of edge, you have the teeth and then a square bar.
What you can see on the ski are the two sides that are next to the labels. Theres edge height and edge thickness.
Let me preface this with the saying that many companies out there will tell you many different things about whats best for rails and ski edges. So take what everyone says with a grain of salt.
We use an edge thats 2.5 mm measured in edge thickness and about 2.3-2.5 mm on the edge height side (a bit of material is lost when we flatten the base). Many companies use different types of edges for different types of skis, so just cause they use something on one doesnt mean it applies to all.
I'm in the belief that beefier is always better for rails, as its just more material that helps resist damage. Edge teeth are sure important, but stuff like teeth pattern, little things, are probably worth more than bigger and deeper teeth in terms of durability. I know we use thick stuff, but I dont doubt that someone may have and use bigger.