I have been looking at some of the rigs in which you tape your negative to AN glass, which is then suspended over the scanner bed so you scan through the AN glass and the negative hanging below it.

How hard is it to get the tape residue off the negative?

Can you scan through AN glass, i.e., could you sandwich a negative between two pieces of glass with the AN surfaces on the inside of the sandwich, and the sandwich then shimmed above the scanner bed so it is not touch the scanner bed? This would be an easy way to have a flat negative and no tape.

How much does AN glass affect the image if you scan through it?