The Scientific Method

So, you have established that the temperature of the coil remains the same regardless of the under hood temperature whether it is hooked up and functional or benign just sitting on the inner fender in the same location.
A true scientific method would be to move each coil around to different locations and record the temperature and output results from each change.
By doing this, you could establish a premium location for the coil and then test the output etc, relating to each change and plot it on a graph.
High end racers and vehicle designers have spent countless time and dollars doing this exact same thing.
Different coils, different locations, wire lengths, and such.
And the compromises to achieve the best results based on budget, output, and reliability factor into it all.
And that's the true scientific method you speak of.