I think the only real unknown at this point is how well it is sealed from the water. That will be the last test, because if it fails the whole sensor is junk. Right now I have to wait to get the PAR meter so I can calibrate it.
If I ever do this again I think I will completely disassemble the sensor and fit the cosine correction dome and the sensor alone in a much smaller acrylic container. Sealing it remains a question.