Can we input different temperature gradients on a well by well basis, or does it have to be a map?

You would need to make a temperature gradient map with interpolated values between the well points. MigriX has some functionality for doing this in the “Grid calculator” in the Explorer window. You would then need to make a .csv table with the well data and use a mathematical operation to convert this into a map. I can send you an example on how to do this.