I believe they describe the ED as Extra Low Dispersion and the ELD as Extraordinary Low Dispersion. You would assume there is some difference or they would refer to them identically.

You could try buying a $15 mount/rings off Amazon with QD and swap the parts. You are taking a significant chance that they may not be the same size.

I'd appreciate any information on the types of coatings each uses and light transmission if available.

I just received my rings and was disappointed to see this issue with the Lugs. Filing down the lug does note sound conducive to building a precision rifle. These should have removable/swappable lug keys. Please address this issue and add a note to the product description.