I recently went through this issue. Maybe one of the postings you read was mine. It's worth going to a dealer or other service location that has an inspection light and having them look around. If there's a leak in the engine compartment it should be easy to spot. There's some debate as to the ability to adequately see the evaporator to inspect for leaks there. I paid about $500 for a new hose and the only bright spot was my system had the dye installed already, as did yours, and that saved me $28 (the cost of the dye). So far so good. I live in Ft Lauderdale and my AC is ice cold. The car is white with tan interior and the windows are tinted.

Oh, if you want to know if your system is low, try reving your engine to about 1500 rpms and see how often the compressor kicks on and off. You'll hear it distinctly. If it comes on and of rapidly you're system is low. At least that's the method used by the private shop I consulted.