That looks very nice for a first attempt. Trace your gun, add 1/2 the slide width + the thickness of the leather for a pretty good stitch line. I also draw a line from the top of thefrontsight to the top of thereafter sight and space the stitch line from that to allow for front sight clearance. Good work!
These are 2 I have come up with. The one for the stamping tools is 2 layers of 1x6 with holes in the top board. The other is a 2$ knife block from goodwill that I drilled to hold various tools I use for punching holes, corners, ect...