Thanks all for the feedback. I'm currently making a .6 scale version of the Rob Roy I've planned out. I know it's an odd scale, but it will be about the right size for my son (who'll no doubt use it as a pirate pouch... I'll probably just put a pirate concho on the lid) and it's good as a test for general fitting.

It does, of course, mean that certain things like hole placements, corner arcs and 'hems' like for the bag top don't work quite the same way, but it's a good starting place.

I fully plan to document the process when I move to a full sized bag.

One more question out there for the Sporran crafting crowd regarding the Day Sporran.

Do you prefer an inside seam (ie sew and then fold right side out) for where the back panel meets the gusset, or a flat edge joined by a visible whip stitch or lacing?