Style3D Atelier - How to Weight Paint in Blender for IMVU

Hi! I've made my mesh and ensured that all the vertices do not clip in Blender, and I have tested the poses that came in the Studiokit and there were no deformations or clipping. HOWEVER when exporting into studio there are parts that clip (the neck, hands and the back of the body) despite playing around with weight paints either at 0% (which is probably the reason for a clipping issue) however even at 100% (red value) it still has a seam? I'm not sure how to fix this in blender as there are no weight influences on parts of the body that is not needed (been checked) I do not want to move any vertices (as the issue can not be replicated in Blender itself) any ideas? Or is this just part of the weight painting process? Any ideas/tips would be extremely helpful thank you!

Your videos are incredibly detailed and useful!