I have few thousand rasters in AK zone 4 state plane on NAD83 and in UTM5/6 on GRS 80 that I am trying to mosaic into Web Mercator. Arc is reporting that I need a transformation but I do not see an esri transformation for it. I understand that the ellipsoids are almost the same. NOAA/NOS's VDatum: A tutorial on datums
What is the recommendation for dealing with this?