I have created an unofficial HiFi support doc of my workflow to rig/skin and export a model for High Fidelity avatar. This free document is called: Avatar Rigging in Blender available here. Soon, it will be available as a HiFi tablet book at CedarLibrary in the HiFi Support book shelf.
Avatar Rigging in Blender is a 16 page PDF including ‘Good To Know’ explanations, so readers can grow in understanding. Also, ‘IMPORTANT!’ flags on crucial bits of information. If you’ve had trouble getting your model into High Fidelity and all you need is the information, this doc should be very helpful.
If you need more help, I will be doing a Rigging Binky Dragon class, with the popular Binky Dragon model. December 3, 2018, 7pm Central Standard Time (UTC/GMT -6 hours) It will be approximately 2.5 hours, screen share meeting(not in VR). The cost is $45USD per attendee. There is limited space. Request enrollment here.