Had safelight do mine too, when I called I told them to send their best because this isn't grandmas Buick. Guy that did it knew about GN's too. I watched the entire hour or so that it took.
I don't know where you live, but there are four glass manufacturer company that I would recommend , they are AFG... Guardian...
Pilkington ... and PPG Industries . All Four companies used a excellent quality of sand made of silicon dioxide and then molted .
And best of all it is a Made In America Product. So what ever vendor you choose ask about those four companies. Good Luck !!