Here is another picture of the outer bag mounted to the cantle with just the snaps holding it in place (no inner lining involved) so I could get a sense of what it would look like when complete.

and then I stitched the bags together. I used some thread tacks in between the two layers to keep the bottom of the liner in place...and then stitched the top edges and side gussets together. I could have done some more finishing and fancy trim work, but made the conscious decision that I wanted this sporran to be very plain with the only "bling" being the red lining. So without further ado, here is the finished product. The bag front:

Back of the sporran:

Front of the sporran with the cantle open:

...and a picture down into the sporran:

Hope you like it!