How to extend VLANs across a RED tunnel

I have found various articles that sound like I can do this... but I need to be clear that it will work so I can plan a purchase.

Requirements:

Setup an Internet connection at a new small office.  This office will not have any local server resources, so the best plan would be to extend my existing VLANs at our HG location to this site.  I need to trunk certain VLANs across the internet to this location so that I can assign device to the same VLANs at HQ location.  Device on these extended VLANs would get DHCP/DNS service from our HQ building and we can apply our LAN based policies just like this LAN was in the main HQ building.  I do not want to create new subnets at this location.

Idea:

I already have an XG430 at the HQ site on Google Fiber.  Install an XG135 or XG210 at the new site.  Build a RED tunnel between the sites.

Create a physical interface on each XG that is assigned to VLANs I want to extend.  Each site XG interface would be connected to a LAN port with all VLANs set to tagged traffic.

RED tunnel would "extend" the VLANs it knows about across the internet, like a QinQ setup, all at layer 2...???

Question:

Would this work?  Has anyone done this before?  I know how to build RED tunnels, have one with another site already.

Here is a diagram of what I am imaging...