How would you operate this kiln?

[kelLOGg]

My kiln is 6' x 6' x 16' with 6" fiberglass insulation on 6 sides, a well sealed door, attic fans for circulation, 2000W baseboard heaters, a home de-humidifier and linear actuator controlled vents with fans. I dry only shed dried wood when it is less than 20% MC.  The way it is currently wired is time-based: when the DH is on the vents are closed and when the DH is off the vents are open and I frequently intervene to change the on-off time. I have let the DHs run until the temperature is 130 - 140 deg F then vent. With this arrangement I successfully dried oak to ~7-8% MC in 2 weeks. The simple furniture I have made (benches, etc.) under these conditions have not cracked nor joints come loose for several years in heated and conditioned space for several years now, so I am satisfied that my drying has been OK, BUT I have fried the DH units due to the high temps. I am now on my third DH unit in about 4 years so I am making changes. I am now trying to keep the temp below ~90 deg F since that mimics the max temp for which the home DH unit is designed but at such low temps I need to use the heat strips for extra heat. At this point I need advice as to the best schedule to operate the heat strips and the DH unit in my kiln. A small Nyle unit would be nice but at $3000 I can't justify it.
Bob

[GeneWengert-WoodDoc]

The time-based DH units were common, but when off, the vents did not open.  The only time the vent opened was when the unit over-heated.  Initially, the DH units had 115 F maximum.  It takes a special unit to run hotter without having poor lubrication and refrigeration failure.  Today's units can potentially run hotter...it depends.  A commercial unit like NYLE can run hotter and will last longer due to coil coatings and metals.  I do think it is a worthwhile,investment.  If you sell the wood or do,custom drying, it is a business and the kiln is a business deduction.