Your kiln is the same as mine. It's been out there for some 20 years and the plexiglass is getting pretty grungy. I also had the fans and directional airflow to begin with and just stopped using it. The upper half of the stack dries real quick, so generally put the thicker stock on top and the one inch furniture grade lower down. I airdry my fresh boards under roof, till they hit 12% and then toss them in the kiln. Within a couple weeks they are 8% or lower. It is mostly pine/spruce which I'm sure dries quicker than hardwoods. Even on cold days, its amazing how warm it gets in there. I'm sure you will be pleased with the results.