Rod Weighing Jig: Take 2

What is it that is between the jig plate and the scale? Better a knife edge or sharp point(s)? I'd think a wide support there would reduce accuracy if that's the word. And I stick to my "guns" although this is just a gut feeling. Seems to me the more you reduce the weight/ mass of the jig, the more accurate changes in the rod will become. A small change that is "more" percentage of the total in other words.

I applaud your efforts. I've assembled engines, but nothing involving blueprint