One of my former Professors (I took "Mechanical Systems, Signal Processing, and Stochastics" from him a few years ago) has published research confirming the efficiency and power of elongated f-holes. The research focuses on violins, but I would imagine these principles should hold true for mandolins as well.
Interesting stuff!
http://newsoffice.mit.edu/2015/violi...tic-power-0210
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