The panels I speak of are under the dash. Remove the one on the passenger side and try to see as much as you can see under the dash.

The fact that you have now CLOSELY examined condensation and not found a trace of dye is a very good thing. Since the car is still making condensation drain water, then it is still cooling. Give the dye a little while to leak out now that you've inspected the condensation drain water. That is the only thing you can't check after the refrigerant has leaked out.

Good luck,