I see, so material takes precedence over diameter in the same kg range. In my example, fluoro would be preferred when fishing for cautious fish, even though it's much thicker.
Going back to my other question, which I think I may not have been clear enough:
In the shop there are some lines in their own category called "Leader materials" and come in rolls of lengths of 15-20m. Do these lines have any specific characteristics that make them more suitable for making into leaders than lines from the "Lines" category (the usual ones of 100m, 150m, 350m etc).