Thanks for your answer, I've used the mesh vertices to get the result I'm after.

In a related question, how about the rotation value found in RegionAttachment, is there a MeshAttachment equivalent for that?

I'm currently making use of the x and y offset values for a RegionAttachment, as part of a calculation to place some non-Spine sprites over the top of a Spine animation. These are the values I'm talking about:

spRegionAttachment *attachment = (spRegionAttachment*)slot->attachment;
float xAdd = attachment->x;
float yAdd = attachment->y;

This all works fine and when I incorporate those values, my positioning is correct. However, for parts of a Spine skeleton that are FFD using Meshes, there is no "x" and "y". So if the attachment type is spMeshAttachment, I'm wondering how I can obtain these same sort of bone offset values? Using my positioning without them has led to these types of attachments being out of place.