Excellent tutorial and a very good explanation of the "correct" way to fit a belt clip.
One thing I've done is to use three very small (size 2 or 3) stainless steel or brass machine screws to reinforce and protect the stitches. I put a one screw at the very top of the stitch line, one at the curve of the edge and one at the point. I get the screws and nuts at Sears Hardware and recess the back of the leather so the nuts sit flush. After I snug them down, i cut off the excess screw length and file them smooth then lightly stake them in place with a center punch so the nuts won't back off.
The screws are smaller and less obvious than rivets. You can dress off the screwdriver slot in the heads if you wish but I don't think it's necessary.