Inset Flanged pillow with welt both sides

I have recently had to master a pillow style that I've spent decades avoiding.  Inset flanges used to inspire, well, terror in me.
Now I've had an order which I'll be delivering this week for inset flange pillows, reversible, with welt ON BOTH SIDES and ZIPPER, and mitered corners on the flanges.
To make it even more challenging, the welt is LEATHER; the fabrics are WOOL; and the last paralyzing detail- one fabric is a plaid and one is a stripe.  On one side the body is the stripe and the flange is the plaid, and on the other side the body is the plaid and the flange is the stripe.

So in addition to practicing and making mock-ups, I made myself a complete pillow, and here is the result, front side:

And the back, with an invisible zipper:

And to prove that it really is one pillow, not two: 

More later in the week!