I don't use a sewing machine, just a needle and thread. I hadn't ever done any sewing before I felt the need to try to make my first holster rig, probably about 20 years or so ago. And I use a pair of "pinking shears" my wife has, that I use to cut out the two pieces of fabric to make the holster (to keep the edges from fraying ... but I still need to "whip" those edges to keep them from deteriorating). I just use ordinary scissors for cutting the elastic and non-elastic straps. Definitely not commercially viable for me to make for sale. It would be nice if some company would produce the design, though.

The white color of the fabric hasn't been a problem for me. In the winter, I wear flannel shirts with a "busy" pattern (with snaps, from Haband) over a white tee-shirt, so they are opaque. In the summer, I wear short-sleeve cotton shirts (again with a busy pattern, and snaps, from Haband). They are much thinner fabric, but the white straps of the rig, and the white holster fabric, aren't noticeable through the shirt.