Here is a
technical analysis from Hitachi Metals Ltd. detailing some of the characteristics and comparisons between their high purity copper wire in 4N HiFC, 6N OFC, and 6N Cu. I'm not sure this will satisfy the desired level of technical specification but it does show some measurable differences between these various purity levels of copper conductors, hope this helps! I find it interesting to see the metallurgical grain structure differences which are also documented.