The temps vary from 60c to 75c. This is still the original configuration though. The fans on the radiator are running at 50%. I haven't added the spill over tank for the pump. The radiator is also still in the sun in the afternoon.
May-be you could replace the fans and radiator (which is, lets face it, the ugly part in the design) by a system where cold water would circulate in the mineral oil tank. (what is the more expensive ? water or electricity ?)
Was wondering, why did you keep the active cooling on the cards ? Do it has any use ? (obviously this time this would void the warranty for sure...)