Edge Offset not doing what I expect it to

I tried posting this earlier but I think I was in the wrong forum or something as it was never posted.

I’m working on trying to learn Blender. I’ve been using 3d programs for about 2 years now on a hobby level basis, learning as I go. I’ve really enjoyed Rhino3D and started using ZBrush Core. But then I found Blender and I’m pretty impressed. The learning curve is steep but I’ve found lots and lots of tutorials, so its great.

I learn best by working on my own project and trying to figure out how to do it. So now I’m working on some simple armor that I plan to 3d print and assemble into real armor.

I’m currently working on the shin guard section. I’ve got the main shape down but now I’m trying to make the “beveled” edge.

I thought the addon Mesh_offset_edge woudl work, but it scales the offset down off the mesh, not along the mesh like I"d like.

Bascially, I want a copy of the entire outside edge brought in like 12mm onto the rest of the mesh so then I could extrude those faces, raising a bevel.

Here is the source photo and a picture of the model I’m working on The gold part from the source image is the part I’m trying to work on, on the outside edge. The middle shin beveled edge I’ll figure out next after this… If my explanation doesn’t make sense, please let me know and I’ll try rewording it.