thanks all. New trane 3ton xl19 system was installed today. The box was rebuilt better than new, and it works great. Dropped the humidity from 80% down to 48% in under two hours.
It's only gotten down to 80 degrees so far, but it feels better in here than it did a couple weeks ago at 74. Anyway, I learned a ton on here, and my stop back by if I decide to do anything about the thermostat, ducts, etc... but it may be fine just the way it is. My bills are gonna go WAY down. There was nothing at all sealing the old box. there was just a giant hole cut in it where the return lines or whatever came through... and it wasn't sealed at all. There were just big holes leading from the garage to the intake. What a joke.
Anyway, I'm off to obsess on the next project. Gotta be a stucco forum somewhere. smell ya later.