There are two versions here, set for 1/2 inch copper pipe.  One without screw holes and one with screw holes.  The screw hole version is more like something you'd pick up at HD, and set for a #6 screw.  I probably would use a little silicone caulk on the non screw version to get it to hold in place.  I'll probably use the non-screw version in the vanity in the pictures.  These were created mostly by Claude.ai, with a lot of coaching from me.  The code is openscad, parameterized and commented so its all easily identifiable and changeable.  Just locate the parameter from the comments and descriptive variable name.