GEMRM... there is a video series on how to make that bag that I'm going to do...It is about 6 hours long. Without the video I wouldn't have attempted it.
Watson
Here's another video about cork handles and she doesn't use anything in the middle....
https://sewsweetness.com/2018/11/vid...v=3e8d115eb4b3
She also makes this rolled handle that does have cording on the inside....
https://sewsweetness.com/2018/12/vid...v=3e8d115eb4b3