With the galvanized steel, you would most likely be looking at an avenger style holster or one that is folded at the sight channel. The reason steel is nice is that's malleable. You can lay it flat, carve your leather, stitch it inside and then curve it to the shape you want already tooled and stitched. The glue and stitch line will keep it in place. It is a process of exploration for you and there is only one way to do it. Prototyping and as you said, to wing it. IT doesn't change the overall design much, but it opens a lot of doors.
Have to agree with Dwight here, 4 layers of molded veg tan can be very solid, and it will take a lot of abuse. I hadn't thought about rawhide. Good call!