This is an old post but given the time of year I feel a reply is appropriate.
As far as food dehydrators go - commercial hop farms dry their hops with
140*F air. No significant lupilin degradation has been found at temps <180*. The biggest problem associated with home dehydrators is the difference in temp from top to bottom. Thus if using one, it is reccomended that you rotate the racks every hour or so. You'll also find inconsistencies, based on design, from side to side on each rack. Typically, you'll find that the cones nearest the center will dry much more rapidly. Therefore, ideally you would want to reorganize the cones on each tray. I, however, do not reccomend this as once the cones begin to dry the lupilin loss becomes exponential upon aggitation. What I reccomend at this point is that you ignore the individual tray inconsistencies and once you reach a nice median dryness place the cones in a sealed bag and place in the refrig for an hour. This allows the cones to exchange moisture content and you have reached a median. Experiment with this and you'll soon become an expert dryer!
Remember also that the in which you pick the cones is vital. Cones are ripe with the bracts have opened and feel papery to the touch, as oppossed to the wet feeling of a green cone. Also, some browning of the lower bracts is a good sign. The oldest cones will be ready sooner so you can either - A. Pick the cones when you've reached a median ripeness across the bine. or B. Pick individual cones on a daily basis based on ripeness. Commercial growers dont have this luxury that we have as homegrowers; they obviously have to use method A.
I hope this was coherent enough to help!
BrewMeister