Air Conditioning - Leaking A.C.

My A.c. System is about 4 years old. I just recently had to replace the coil and both drip pans. The problem is too much water build up inside the coil housing. Although it drips out the main line, it is not clogged, the water builds up and spills over the pan into the plenum. This in turn spills over to the over flow pan. This problem caused the original pans, coil housing, and coil to prematurely rust out. I just installed a V style coil and housing, with a plastic inner pan. As luck would have it, I noticed water coming out of my over flow line. I inspected and the water is spilling over the inner pan still. The coil housing seems to slope toward the plenum and the inner pan is slopped as well. What can I do to get this water to drain out of the housing and not spill over? I have no room to raise the plenum...in turn, I cannot raise the coil housing.

You seem to be removing an awful lot of humidity. You don't use a programable set-back t-stat do you? If so skip it and run it at one temp 24/7. Also see if you can tell if the fan is set to high speed and make sure you've got a clean filter and plenty of air flow.