I may be burned at the stake as a heretic, but the weight savings vs the effort is not worth it for this part. I did not like my first efforts at making these, so I bought more stock and kept at it. I finally got ones I liked using my chop saw to cut the angle. All told I probably saved about 10 french fries worth of weight. Yes, if you keep adding all the bits of weight saved for the whole plane together it is a pound or two. There just isn't much variation allowed in a 12 to amount to a real weight savings. It is more of an attitude than a real difference in this plane.
If you are having a problem, just drill and tap, and forget the 30 deg angle. Yeah, it looks keen, and it shows the right attitude, but it will make zero difference in your final weight.
I gained 30 pounds of useful load on my plane when I stopped eating junk food.