So does it stand to reason that the barrels with the most steel (white swirl) in them are the superior barrels and thus, the percentage of white the barrel, a fair indication of the quality of a damascus barrel; or is there anything good about having iron in a barrel?

It would appear that in the Greener photo I posted above, there is a lot of steel in those barrels (is this an example of the famous 70% Birmingham damascus...actually it looks like it might have a bit more than 70% white swirl)?