Here is a little hack I’m using to tackle a problem you might have come across!
So you made a really cool outfit in Lens Studio with (for example) a skirt, a shirt and matching sunglasses?
However, the Sunglasses attached to the Face Tracker keep on losing the tracking when you move too far away from the camera?
Attach the sunglasses to the Head bone of the 3D Body Tracking armature!
Like that, the sunglasses won’t lose tracking as Body tracking has a bigger camera-distance range for recognition!