I thought directly under the basking spot it was supposed to be 90. There is plenty of variation as it gets down to about 70 on the cold side on the surface.
And is it OK not to feed him until he sheds? I haven't fed him for a week since he refused to eat on tuesday, his mouse day, and I can't find my other mice. But I was wondering if most garters refuse to eat while shedding or before shedding (which I think is true).