The recessed zipper closure challenge.

A few weeks ago I made myself this bag:

Fabrics: dark brown linen and a Kaffe Fassett print.
I use it to hold my clarinet case, musicnotes, reed case, pencils etc.
As you can see it has difficulties standing upright; I interfaced it with Vilene S 320.
When my sister saw this bag, she asked me to make a similar one for her." Of course, I can do that", I said. "And... I would like it to be closed at the top".
"Sure", I said, "no problem".
Only afterwards I realised, I had never installed a recessed zipper closure before!!
Online, I went, in search of a suitable tutorial.
For me ,the best one is this tutorial from Sarah of ´My spare time`.
Sarah explains all the different steps very clearly.
The only problem with all the tutorials is , that they are made for narrow bags.
My bag has a broad base and I also wanted the top to be wider.

 See what I mean?At the top, the bag is too `sharp`
I wanted it to look this way:

I achieved it by sewing, from the inside by hand, some 6 cm of the lining, which is hanging loose, to the outer bag. This way, the side of the bag is pulled to the middle.
Are there others ways to get this result?
Anyway, here is the bag!

Fabrics: brown linen, lovely eyecatching leafpattern cotton fabric from Philips Jacobs.
I used Vilene S 520 as interfacing; this bag is much sturdier and can stand on its own . It is just a little tricky to turn the bag inside-out, once you stitched outerbag and lining together.
The bag closes with the recessed zipper. I added pockets inside and a key hook. 
Ironing gives the finishing touch.
I learned a lot by making this bag; but I especially hope my sister likes him/her...
Kristien