I think you missed a few magical words that might help!
You want a "provisional skip" to test out the waters :-) Go with the "I completely understand that sometimes these situations are not successful for the student and I would never want to put my child in a negative situation. However, all of my research shows that it is a good option that we'd like to consider. So we would like to move him provisionally to 2nd grade. We could meet 4 and 8 weeks into the school year to determine if he's adjusted well and to identify any gaps I can fill at home."
Admin wants a way out. If you offer it to them that this is not the end all be all, they may be more willing to bite. In addition, you can always ask them to consider a mid-year skip with 1st for a semester and 2nd for a semester.
